Optical cochlear implant has been occuring as a new cochlear implant which utilizes laser pulses to stimulate hearing. Compared to electronic cochlear implant, it has demonstrated higher spatial selectivity and less radiation scattering, which could lead to higher fidelity cochlear prostheses. At present, most investigations have focused on experiments in vivo. Although a lot of exciting results have been obtained, the mechanisms of laser stimulation is still open. In this paper, a brief review on the recent new findings of optical cochlear implant is given, and possible mechanisms are discussed. In the end, new experimental proposals are suggested which could help to explore the mechanisms of laser-cochlea stimulation.