A VST-HMD (Video See-Through Head Mounted Display) includes at least one camera, a first display device, a second display device, a first lens, a second lens, a first eye tracker, a second eye tracker, and a processor. The camera captures environmental image information. The first eye tracker detects left-eye motion information of a user. The second eye tracker detects right-eye motion information of the user. The processor obtains an eye focus region of the user and depth information of the eye focus region according to the environmental image information, the left-eye motion information, and the right-eye motion information. The processor monitors a displacement of the eye focus region and a change in the depth information, and accordingly determines whether to adjust image positions of the first display device and the second display device.一種視訊穿透式頭戴顯示器，包括：至少一相機、一第一顯示器、一第二顯示器、一第一透鏡、一第二透鏡、一第一眼球追蹤器、一第二眼球追蹤器，以及一處理器。相機係用於擷取一環境影像資訊。第一眼球追蹤器係用於偵測一使用者之一左眼活動資訊。第二眼球追蹤器係用於偵測使用者之右眼活動資訊。處理器係根據環境影像資訊、左眼活動資訊，以及右眼活動資訊來取得使用者之一眼睛專注區域和眼睛專注區域之一深度資訊。處理器更用於監控眼睛專注區域之一位移量和深度資訊之一變化量，再據以判斷是否要調整第一顯示器和第二顯示器之影像位置。
