To solve the re-entry control problem of reusable launch vehicle (RLV), a reaction control system (RCS) based on fuzzy logic was presented. The characteristic of RCS was analyzed deeply, and the RCS model based on effect coefficient and relay feature was built. Then the three-channel RCS controller based on fuzzy logic by using the expertise knowledge was designed. Both of the attitude angles and attitude angles- rate errors were used to be the controller-s inputs. These inputs were processed by fuzzy logic controller, and then the RCS commands to each channel were generated. This controller was testified in the 6 degree of freedom simulation system and compared its effect with proportional-integral-differential (PID) controller. It was proved by the simulation results that the controller has better tracking performance and the RCS outputs are more efficient.