Abstract: The slow response characteristics of output current signal of rhodium self-powered neutron detectors (RSPND) has seriously affected the real-time response of the neutron flux rate  measurement in the reactor, which is not conducive to real-time control and safety management of reactor. Inverse function calculation or various compensation methods are used to improve the response characteristics of RSPND, which is beneficial for the application of RSPND. This paper studies the forward differential transform method, backward differential transform method, step response method and bilinear transform method of four kinds of digital processing algorithms, and the response time for the output signal of the vanadium self-powered neutron detector is shortened effectively. The time constant is reduced to less than 5 seconds. The digital experimental system verifies the correctness of the algorithm, which provides the possibility for the rapid response of rhodium self-powered neutron detectors in the measurement the neutron flux rate in the reactor.