At present, rockets are often modified as low-cost targets. In order to enhance the observability of the target, a light pipe is now installed on the opening of the body to emit strong light during flight to display track information. In this paper, the three-dimensional flow field around the rocket target tracer is simulated using CFD simulation software. The effect of aerodynamic coupling on aerodynamic characteristics and stability in different opening modes is studied. It is concluded that the negative rolling torque generated by the rocket target tracer at the trailing orifice acts on the tail wing to make the pressure and density distribution of the blade asymmetric. As a result, the resistance coefficient and static moment coefficient of the projectile are increased, the lift coefficient is decreased, and stable reserve is reduced.