Taking a certain type of electro-hydraulic proportional load-sensitive multi-way valve as the research object, the AMESim simulation model of its electro-hydraulic proportional system was constructed. By setting the gap and eccentricity at the main valve spool, the influence of the amplitude and frequency of the external flutter input signal and the diameter of the front orifice of the internal main valve on the fluctuation of the main valve spool displacement and output flow were obtained when the leakage was considered. The results show that as the signal frequency increases and the amplitude decreases, the fluctuation amplitude of the two parameters gradually decreases; the diameter of the orifice affects the overshoot and the response time, but also affects the fluctuation amplitude of the parameters. The simulation analysis results can provide reference for the determination of flutter signals in practical applications.