In the daily operation training of radar, the simulation training system can better solve the problem of limited use of real equipment. The A-scope display data of radar echo simulation can reduce the cost of simulation training system and improve the flexibility of the system. In this paper, a simulation algorithm is proposed, which is based on the fidelity, real-time and interoperability of A-scope display. The information of A-scope display is divided into five parts according to the distance. The radar echo is simulated according to the characteristics of signal amplitude by combining the radar beam, sea clutter statistical data, target echo and system gain models. In addition, the simulation algorithm can respond to the radar operation instructions in real time and update the A-scope display data according to the different working conditions of the radar. The experimental results are close to the real echo effect and meet certain operational training requirements.