The astigmatism Z5 in the etching process of lithographic lens silicon wafer can greatly deteriorate wave aberration of the lithographic lens. In order to compensate the astigmatism in real time, this paper proposes an astigmatism active Z5 compensation system that includes real time data platform, actuator system, flexible supporting structure and optical lens. The sphere interferometer is used as test equipment for optical lens surface shape. The least square method and the linear superposition principle are both used to determine the relationship between actuate parameter and surface shape. The experiments, including test of response function of actuator in active compensation system, test of compensation stroke, test of compensation precision, test of compensation resolution, are conducted. The results show that the astigmatism Z5 compensation stroke of the system is up to 735 nm. The astigmatism Z5 compensation precision is less than 2 nm with the high-order aberration less than 1 nm. The astigmatism Z5 compensation resolution is 2 nm. The system can effectively compensate the wave aberration in the lithographic lens system and satisfy the image quality requirement of lithographic lens.