A novel topology circuit of three-phase active compensation is discussed to be used to manage negative sequence caused by locomotive load in high-speed electrification railway. The main circuit uses a three-phase two-leg compensator as active elements of shunt hybrid active compensator topology. The switch devices’ number of this topology is reduced by two comparing with three-phase full-bridge active inverter, and the cost is lower. A new coordinates alternate method and matrix applied to detecting for reactive power, negative sequence and harmonic is presented due to the two-leg in inverter, calculation and storage are reduced, the computational speed is improved. The simulation model is developed by analyzing working principle, control principle and strategy with Simulink. The simulating results indicate that the shunt hybrid active compensator could restrain the problem of negative sequence generated by locomotive load, reduce the effect of reactive power and negative sequence, and improve electric energy quality. And the correctness of the proposed structure and control method is verified.