In order to study the surge wave characteristics of pumped storage power station with upstream and downstream surge chambers under small fluctuations, the mathematical model of small fluctuations in a pumped storage power station with this type of arrangement was derived based on the state-space method. The time-domain process of surge wave in the upstream and downstream surge chambers was solved by numerical simulation. The frequency-domain process of surge wave in the upstream and downstream surge chambers was obtained by the fast Fourier transform (FFT). Without considering the hydraulic coupling between the speed regulating system and the surge chamber system, the transfer function between the pressure pipeline flow and the water level of the surge chamber was established to obtain the amplitude-frequency characteristics of the surge chamber systems. The results show that the input signal frequency corresponding to the maximum amplitude of the surge wave in the upstream and downstream surge chambers is similar to the natural frequency of the surge chamber system, and the surge wave oscillation frequency in the surge chamber corresponds to the tail wave oscillation frequency of the unit speed. The surge wave characteristics of the surge chamber are closely related to the area of the surge chamber and the head loss coefficient of the water delivery tunnel. Increasing the area of two surge chambers can reduce the frequency and amplitude of surge wave in the upstream and downstream surge chambers, and enhance the stability of the system. The variation of head loss coefficient of the tunnel has no impact on the oscillation frequency of surge wave in the upstream and downstream surge chambers, but has a great impact on surge wave amplitude in the upstream and downstream surge chambers. The larger the head loss coefficient is, the smaller surge amplitude is, the system stability is better.