Abstract: In order to improve the mixing performance of coaxial injectors for attitude and orbit control liquid rocket engine, a two-rectangle jet generator was designed. Then, the plasma flow control experiments were carried out to obtain the flowfield and velocity profile of jets. The results show that the two-rectangle jet has good similarity, which is similar to the single jet. When the velocity difference of two jets increases, the similarity gets better, and the mixing point moves to the generator exit. Meanwhile, the mixing angle and the mixing ratio increase, but the maximal value of vorticity decreases. The influence of plasma on the similarity is weak, but it can increase the jet velocity near the generator exit, the jet width and the mixing angle. It can also shorten the potential core length, make the mixing point move to the generator exit and expend the high vorticity domain. However, the positive and negative values of vorticity sum are about the same size, and their mixing ratios are close to each other. With the increase of jet velocity difference, the plasma control effect decreases. In general, the plasma actuator should be setted in the low-speed jet. Increasing the mixing angle is more effective than controlling the location of mixing point.