Compared with traditional optical lenses, liquid lenses have the advantages of fast response, large zoom range, and high controllability, which are widely required in various fields, such as vision correction, microscopes, cellphone cameras, endoscopes, and bionic optics. This paper summarizes the technical developments in liquid lenses and briefly describes their working principle at home and abroad. Furthermore, it analyzes the related processing methods, performance indices, and application prospects of some typical liquid lenses. Finally, this work provides an outlook on the future development trend to provide useful references for further research on liquid lenses.