As the output voltage of the signal acquisition module is interfered by power frequency magnetic field (PFMF) in electric vehicle battery management system (BMS). A kind of anti-PFMF interference acquisition module design is put forward. According to the mechanism of the PFMF interference in BMS signal acquisition module, the software and hardware anti-interference filter is designed. Under the anti-PFMF interference test, results show that the optimized BMS acquisition module not only has simple construction, but also can effectively filter out 50 Hz frequency interference and improve the BMS acquisition module anti-electromagnetic interference performance .Finally, it has a reference value in electrical vehicle anti-electromagnetic interference.