For the strict demand of Wiegand code acquisition system about electromagnetic compatibility, real-time and reliability etc in a certain area of intelligent surveillance system for nuclear power plants, a set of Wiegand signal acquisition system was designed. By constructing a single frame data buffer based on community, an efficient two stage software filtering algorithm and data buffer refreshing mechanism was used to balance the effectiveness of real-time acquisition and filtering. The results show that the system can realize the Wiegand code with high confidence and high real-time acquisition, improve the anti-interference performance of the system and anti noise performance.