A head mounted display (HMD) device and an image projection method are provided. The head mounted display device includes an optical waveguide device, an image device, an optical conversion layer and a processor. The optical waveguide device receives an image light beam and projects a projection image through a surface. The image device is used to provide the image light beam. The optical conversion layer is disposed overlapping the edge of the surface of the optical waveguide device. The optical conversion layer deflects a portion of the projection image to generate an adjusted projection image according to a command signal, so that the adjusted projection image is transmitted to a projection target. The processor generates the command signal according to a position of the projection target.