Cartridge inserted valves are widely used in hydraulic applications because of their large flow capacities, simple structure and low cost. In this paper, a two-stage cartridge inserted proportional throttle valve was investigated. The main stage of the two-stage poppet type proportional throttle valve is based on flow amplification principle, and a single-stage servo proportional direction valve is used in its pilot stage. We first established a simplified mathematical model, and obtained the qualitative expressions under simplified conditions. Then, we set up a simulation model of the proportional throttle valve by means of SimulationX, and verified the correctness of the model with experimental data. Finally, we used the verified simulation model to analyze the performance of the proportional throttle valve. The results show that there is a dead zone and time lag of the output flow and the flow gain of the main stage is variable. The performance of the proportional throttle valve is affected by the underlap and the area gradient of the feedback slot, the volume between the pilot and the main stages, and flow capacity of the pilot stage, etc.