Liquid crystal spatial light modulator (LCSLM) can realize beam steering by modulating wavefront tilt. Compared with fast steering mirror (FSM), LCSLM is smaller, lighter and lower power consumptive in a nonmechanical way. Thus, it can be applied as a beam steering control device in laser communication. The principle of liquid crystal beam steering is introduced. A closeloop control experiment is designed based on LCSLM to realize beam steering according to the modulation characteristic of LCSLM tested. The experimental results show that LCSLM can suppress jitter effectively. The relative error is less than ±1.75%. The influence of diffractive effect on beam quality is analyzed, as well as the restriction of response time of liquid crystal, transmission delay and algorithm complexity on control bandwidth.