According to the specific property of traction supply system, a novel hybrid active power filter (HAPF) is designed in this paper. The new HAPF topology is that, after the impedance of fundamental wave is in parallel with the active power filter (APF), it is series connected passive filter. The kinds of structure can reduce the VA rating of the APF greatly. The small rating active power filter is used to improve filtering characteristics of the passive filter and suppress possible resonance between the traction supply system impedance and the passive filter. Through MATLAB simulation, it shows that the control strategy of power quality is apparently effective, and it plays an important role in enhancing the reliability of transformer station and the operating security of electric railway.