diff --git a/pkg/server/events.go b/pkg/server/events.go
index 87169b544..2c510a953 100644
--- a/pkg/server/events.go
+++ b/pkg/server/events.go
@@ -213,7 +213,7 @@ func (em *eventMonitor) handleEvent(any interface{}) error {
 		} else if err != store.ErrNotExist {
 			return errors.Wrap(err, "can't find container for TaskExit event")
 		}
-		// Use GetAll to include sandbox in unknown state.
+		// Use GetAll to include sandbox in init state.
 		sb, err := em.c.sandboxStore.GetAll(e.ID)
 		if err == nil {
 			if err := handleSandboxExit(ctx, e, sb); err != nil {
@@ -313,13 +313,13 @@ func handleSandboxExit(ctx context.Context, e *eventtypes.TaskExit, sb sandboxst
 		}
 	}
 	err = sb.Status.Update(func(status sandboxstore.Status) (sandboxstore.Status, error) {
-		// NOTE(random-liu): We SHOULD NOT change UNKNOWN state here.
-		// If sandbox state is UNKNOWN when event monitor receives an TaskExit event,
+		// NOTE(random-liu): We SHOULD NOT change INIT state here.
+		// If sandbox state is INIT when event monitor receives an TaskExit event,
 		// it means that sandbox start has failed. In that case, `RunPodSandbox` will
 		// cleanup everything immediately.
-		// Once sandbox state goes out of UNKNOWN, it becomes visable to the user, which
+		// Once sandbox state goes out of INIT, it becomes visable to the user, which
 		// is not what we want.
-		if status.State != sandboxstore.StateUnknown {
+		if status.State != sandboxstore.StateInit {
 			status.State = sandboxstore.StateNotReady
 		}
 		status.Pid = 0
diff --git a/pkg/server/sandbox_run.go b/pkg/server/sandbox_run.go
index 3f2d206f3..f844a0107 100644
--- a/pkg/server/sandbox_run.go
+++ b/pkg/server/sandbox_run.go
@@ -85,7 +85,7 @@ func (c *criService) RunPodSandbox(ctx context.Context, r *runtime.RunPodSandbox
 			RuntimeHandler: r.GetRuntimeHandler(),
 		},
 		sandboxstore.Status{
-			State: sandboxstore.StateUnknown,
+			State: sandboxstore.StateInit,
 		},
 	)
 
@@ -258,7 +258,7 @@ func (c *criService) RunPodSandbox(ctx context.Context, r *runtime.RunPodSandbox
 		return nil, errors.Wrap(err, "failed to update sandbox created timestamp")
 	}
 
-	// Add sandbox into sandbox store in UNKNOWN state.
+	// Add sandbox into sandbox store in INIT state.
 	sandbox.Container = container
 	if err := c.sandboxStore.Add(sandbox); err != nil {
 		return nil, errors.Wrapf(err, "failed to add sandbox %+v into store", sandbox)
@@ -269,7 +269,7 @@ func (c *criService) RunPodSandbox(ctx context.Context, r *runtime.RunPodSandbox
 			c.sandboxStore.Delete(id)
 		}
 	}()
-	// NOTE(random-liu): Sandbox state only stay in UNKNOWN state after this point
+	// NOTE(random-liu): Sandbox state only stay in INIT state after this point
 	// and before the end of this function.
 	// * If `Update` succeeds, sandbox state will become READY in one transaction.
 	// * If `Update` fails, sandbox will be removed from the store in the defer above.
@@ -279,8 +279,8 @@ func (c *criService) RunPodSandbox(ctx context.Context, r *runtime.RunPodSandbox
 	//   * If the task is running, sandbox state will be READY,
 	//   * Or else, sandbox state will be NOTREADY.
 	//
-	// In any case, sandbox will leave UNKNOWN state, so it's safe to ignore sandbox
-	// in UNKNOWN state in other functions.
+	// In any case, sandbox will leave INIT state, so it's safe to ignore sandbox
+	// in INIT state in other functions.
 
 	// Start sandbox container in one transaction to avoid race condition with
 	// event monitor.
@@ -293,8 +293,8 @@ func (c *criService) RunPodSandbox(ctx context.Context, r *runtime.RunPodSandbox
 		// see the sandbox disappear after the defer clean up, which may confuse
 		// them.
 		//
-		// Given so, we should keep the sandbox in UNKNOWN state if `Update` fails,
-		// and ignore sandbox in UNKNOWN state in all the inspection functions.
+		// Given so, we should keep the sandbox in INIT state if `Update` fails,
+		// and ignore sandbox in INIT state in all the inspection functions.
 
 		// Create sandbox task in containerd.
 		log.Tracef("Create sandbox container (id=%q, name=%q).",
diff --git a/pkg/store/sandbox/sandbox.go b/pkg/store/sandbox/sandbox.go
index 764b2760b..69189069f 100644
--- a/pkg/store/sandbox/sandbox.go
+++ b/pkg/store/sandbox/sandbox.go
@@ -93,7 +93,7 @@ func (s *Store) Get(id string) (Sandbox, error) {
 	if err != nil {
 		return sb, err
 	}
-	if sb.Status.Get().State == StateUnknown {
+	if sb.Status.Get().State == StateInit {
 		return Sandbox{}, store.ErrNotExist
 	}
 	return sb, nil
@@ -123,7 +123,7 @@ func (s *Store) List() []Sandbox {
 	defer s.lock.RUnlock()
 	var sandboxes []Sandbox
 	for _, sb := range s.sandboxes {
-		if sb.Status.Get().State == StateUnknown {
+		if sb.Status.Get().State == StateInit {
 			continue
 		}
 		sandboxes = append(sandboxes, sb)
diff --git a/pkg/store/sandbox/sandbox_test.go b/pkg/store/sandbox/sandbox_test.go
index 538e573d9..23523e292 100644
--- a/pkg/store/sandbox/sandbox_test.go
+++ b/pkg/store/sandbox/sandbox_test.go
@@ -106,7 +106,7 @@ func TestSandboxStore(t *testing.T) {
 			},
 			NetNSPath: "TestNetNS-3defg",
 		},
-		Status{State: StateUnknown},
+		Status{State: StateInit},
 	)
 	assert := assertlib.New(t)
 	s := NewStore()
diff --git a/pkg/store/sandbox/status.go b/pkg/store/sandbox/status.go
index 6dedb8ae3..4bd6745f9 100644
--- a/pkg/store/sandbox/status.go
+++ b/pkg/store/sandbox/status.go
@@ -22,15 +22,15 @@ import (
 )
 
 // State is the sandbox state we use in containerd/cri.
-// It has unknown state defined.
+// It has init state defined.
 type State uint32
 
 const (
-	// StateUnknown is unknown state of sandbox. Sandbox
-	// is in unknown state before its corresponding sandbox container
-	// is created. Sandbox in unknown state should be ignored by most
+	// StateInit is init state of sandbox. Sandbox
+	// is in init state before its corresponding sandbox container
+	// is created. Sandbox in init state should be ignored by most
 	// functions, unless the caller needs to update sandbox state.
-	StateUnknown State = iota
+	StateInit State = iota
 	// StateReady is ready state, it means sandbox container
 	// is running.
 	StateReady
diff --git a/pkg/store/sandbox/status_test.go b/pkg/store/sandbox/status_test.go
index 6973ac66c..31e9253ee 100644
--- a/pkg/store/sandbox/status_test.go
+++ b/pkg/store/sandbox/status_test.go
@@ -28,7 +28,7 @@ func TestStatus(t *testing.T) {
 	testStatus := Status{
 		Pid:       123,
 		CreatedAt: time.Now(),
-		State:     StateUnknown,
+		State:     StateInit,
 	}
 	updateStatus := Status{
 		Pid:       456,