An optical object distance simulation device is disclosed. The device has an optical lens module composed of a plurality of optical lens and the optical lens module is arranged between an optical lens and a chart for simulating the real object distance and reducing the space required for testing an optical lens. Moreover, the optical lens module is separated from a light-emitting element, a power supply or any heat-generating elements all separated from the optical lens module. Furthermore, the heat-dissipating elements are arranged near elements that generate substantial heat. Hence, not only does the present invention have a good heat-dissipating effect, but it also prevents external dust from polluting the optical lens module because of the positioning of the heat-dissipating element and the heat-dissipating hole.