Abstract: Optical lattice clocks have achieved a system uncertainty on the level of 10^-18 and a frequency stability of 10^-19, and are one of the candidate devices for redefinition of the SI second. Benefiting from excellent performance, they are increasingly playing an important role in the field of basic physics research. In this paper, the background, principle, key experimental techniques, and applications of optical lattice clocks in fundamental research are reviewed.