Combined with the feature of near-surface electromagnetic emission signals in the frequency domain，an average current and a voltage feedback control were introduced.A digital dual-loop feedback control system was built based on DSP (Digital Signal Processor).A feedback model was also built in z domain to make the system stable.The steady voltage in low frequency and steady current in high frequency were realized.The amplitude of the load-current range of transmitting antennas was reduced，while the requirements of antenna design were decreased.The problems that the broadband detection transmitter is not enough to cause the antenna current damping in the high frequency and the broadband detection transmitting is not stable to the large current in low frequency were avoided.Further，a protection of circuit was provided.Through comparing the simulation after the introduction of dual-loop feedback and open-loop，the parallel dual-loop feedback output current variation was 8.5% of that for open-loop with low to high frequency.The measured results achieve the purpose of design and provide references for the improvement of near-surface electromagnetic launch system.