Microspheres can modulate the light field and focus the incident beam into an extremely narrow area on the back of the microsphere, so that the incident beam's full width at half maxima is smaller than the optical diffraction limit, and the focused intensity is considerably higher than the incident one. In addition, the microspheres have high numerical aperture characteristics, which can improve the collection efficiency of detection signals. Based on these benefits, microspheres offer a novel concept and method for realizing optical super-resolution imaging and fluorescence enhancement. Super-resolution imaging and fluorescence enhancement technologies based on optical microspheres are simpler, more direct, and easier to implement than traditional technologies. Their imaging and enhancement effects are comparable to those of traditional technologies. They have significant research value and application prospects in biological imaging and medical detection. Although the studies on microsphere-modulated light field to achieve fluorescence enhancement has made significant progress in recent years, review papers focusing on this topic are still limited. A systematic summary of microsphere-enhanced fluorescence and microsphere-modulated light field is critical for future studies and developments in this field. First, microsphere-based optical super-resolution imaging, including bright field super-resolution imaging and fluorescence super resolution imaging, is introduced. Subsequently, the microspheres-based fluorescence enhancement research is described, including phenomenon research, mechanism exploration, and discussion of influencing factors. Finally, the progress and applications of microsphere-based super-resolution imaging and fluorescence enhancement are summarized, and the future development challenges and trends in this field are discussed and prospected.