Cruise missile is an important threat in modern air defense field. The research of cruise missile target scattering characteristics plays an important role in radar detection efficiency. In this paper, a new dynamic RCS modeling method for cruise missile target is proposed to solve the problem that the static RCS data does not fit the radar detection. Based on the scene of airborne early warning radar detecting cruise missile flying at low altitude, the target model is emulated by CST software, and the static omnidirectional RCS simulation data of the target under S-band operating condition are obtained. Combining the target motion simulation trajectory and the radar motion trajectory, the radar line-of-sight angle is calculated by 3D coordinate transformation, and the dynamic RCS data of cruise missile is obtained by searching the static RCS database based on the line-of-sight angle. The simulation results can provide data support for capability evaluation, parameter optimization and target identification of radar detection cruise missile.