Compared with traditional electro-hydraulic servo valve(EHSV),the cartridge electro-hydraulic servo valve further has high power-to-weight ratio and excellent dynamic characteristics.A cartridge two-dimensional electro-hydraulic servo valve was proposed and its dynamic characteristics were studied especially.According to the structure of the cartridge 2D EHSV valve and its working principle,its mathematical model was built and analyzed,the rotational viscous damping coefficient was studied in detail especially.The simulation results show that:the rise time is about 10 ms and the amplitude-frequency bandwidth is about 40 Hz of the open-loop model,while the rise time is about 4 ms and the amplitude-frequency bandwidth is about 100 Hz of the closed-loop model.Furthermore,a test platform was built to test the dynamic characteristics of the cartridge 2D EHSV valve.The experimental results show that the rise time of the step response is about 7 ms and the amplitude-frequency bandwidth is approximately 38 Hz under the open-loop control,while those are 6 ms and 117 Hz under the close-loop control.The test results agree with the simulation results and the cartridge 2D EHSV has excellent dynamic characteristics.