In this paper, a new type of Rogowski digital integrator signal processing system has been developed for the dc test platform which located in the Institute of Plasma Physics. This signal processing system is mainly composed of the dual-coil subtraction structure and the digital signal filtering processing method that comb filter combined with high-pass filter (HPF) and low-pass filter (LPF). Trigger noise comes from the converter; it can be coupled to the integrator through distributive capacitance between dc bus bar and Rogowski coil; it will affect the integrator seriously; for example, the amplifier in integrator will be saturation, and the integrator cannot work, burrs lying in integration result. The dual-coil subtraction structure can attenuate the trigger noise significantly from hardware perspective and is convenient for the integrator to take a high gain without saturation. The comb filter combined with HPF and LPF can attenuate the trigger noise further and smooth the integration result. The experiment indicates that the approach proposed in this paper can reduce the impact of trigger noise on the integrator and improve the measurement accuracy.