In this paper, the antenna system designed for radar simulator was described. The system used horn antennas toconstitute amplitude ratio angle measuring system, to solve the contradiction between azimuth beam width and antennagain. It had a simple structure, ease of implementation, high antenna gain and high precision in angle measurement. Bymeasuring angle error analysis and electromagnetic simulations, it was proved that main technical indicators such as gaincoefficient, measuring angle range and angle measurement precision of antenna system met the design requirements of ra.dar simulator, therefore, it had application value.