Abstract: The decline of wireless channel is a key factor that hinders the reliability and validity of wireless communication. The emergence of multi-input multi-output system can solve this problem effectively. However, the implementation is extremely difficult because of the impact caused by terminals. Cooperative communication improves diversity gain by using the traveling carriage of single antenna to share other users’ antennas in multi-user environment. However, relay node selection of cooperative communication is a primary key problem to be solved. This study, presented relay node selection algorithm evaluation indicators according to the reliability and validity of communication and classified the existing relay node selection algorithms according to the indicators. The study analyzed and compared several common algorithms, finding out their advantages and disadvantages, providing a clear direction for relay node selection of cooperative communication.