In this paper, the influence of plasma on the radar scattering cross-section characteristics of the target is studied, and the results show that the plasma cladding affects the radar scattering cross-section (RCS) characteristics of the detected target. Through electromagnetic simulation, the relationship between plasma density, collision frequency and RCS, and the relationship between incident wave frequency and plasma parameters are studied. In this paper, the RCS characteristics of a metal cone covered with plasma are simulated. By changing the plasma parameters in the model, RCS data at different detection frequencies (10GHz, 15GHz, and 20GHz) were observed. The results show that the overlay plasma has a great influence on the RCS characteristics of the metal. By changing the incident wave frequency and plasma density, the specific influence law on RCS data were obtained.