A head mount personal computer (HMPC) and an interactive system using the same are provided. The provided HMPC includes a microprocessing unit, an output unit and an image capture unit with a distance detection function (ICWDD). The microprocessing unit is served as an operation core of the HMPC. The output unit is coupled to and controlled by the microprocessing unit, and configured to project an optical image onto a space. The ICWDD is coupled to and controlled by the microprocessing unit, and configured to capture operation gestures on the projected optical image from a user wearing the HMPC, such that the microprocessing unit correspondingly controls operations of the HMPC in response to the operation gestures on the projected optical image from the user.