A digital diagnostic system with interchangeable lenses includes a host and at least one optical lens module, wherein the host without any optical lens having curved surface includes a focus adjustment module which drives an image capture module to linearly move. Therefore, the optical system of the optical lens module can be designed independently, and no need to include focus adjustment mechanism, so that the optical design of the optical lens module can be greatly simplified, and the system allows a greater mechanism tolerance, thereby reducing manufacturing difficulty and manufacturing cost.
