Abstract: Gas-liquid cyclone separator can realize gas-liquid separation in the working conditions of high gas speed and high gas/liquid ratio and can satisfy national requirements on cost reducing and efficiency increasing. In this paper, domestic and foreign research achievements on undersea gas-liquid cyclone separators were investigated, and different types of undersea gas-liquid cyclone separators were mainly reviewed. Then, the theoretical research progress of undersea gasliquid cyclone separator was discussed from the aspects of the breakage mechanism of droplet in the swirling flow field and the internal flow field parameters of separator. Finally, based on the actual engineering demands, the disadvantages and future development direction of the researches on undersea gas-liquid separator were pointed out. It is recommended to establish an independent design criterion for undersea gas-liquid cyclone separator, further improve the theoretical researches on droplet breakage and coalescence in the swirling flow field, and combine the gasliquid cyclone separator with other forms of separators to establish an integrated separation system.