The disclosure provides a head mounted display device, comprising a house and an optical glass, a telescope, an imaging lens assembly and a display screen located in the house. The house further comprises a display window and a view window. The telescope is located corresponding to the view window. The optical glass and the telescope are collocated along a first optical axis. The imaging lens assembly and the display screen are collocated along a second optical axis. Light emitted by the display screen passes through the imaging lens assembly and the optical glass and projects out the house through the display window. Or, light of outside world passes through the view window and the telescope and projects out the house through the display window. User can watch outside scenes through the head mounted display device.