Microlens array is a multi-functional micro-optical element that can modulate incident light to realize beam expansion, beam shaping, light splitting, and optical focusing, and further to achieve large viewing angle, low aberration, small distortion, high time resolution, and infinite depth of field. Microlens array has important application potential in miniaturization, intelligence and integration of optoelectronic devices and optical systems. This review article first describes the design principle and development history of microlens arrays. Then the recent progress on the fabrication of microlens arrays including inkjet printing, laser direct writing, screen printing, photolithography, photopolymerization, thermal reflow, and chemical vapor deposition is reviewed. In addition, the applications of microlens arrays in the fields of imaging sensors, lighting, display, and solar cells are summarized. Finally, the future development directions are prospected, and the development trend and future challenges of curved microlens, superimposed compound eye system and the combination of microlens with new optoelectronic materials are discussed.