In the study of open and shut characteristic detection system for four-circuit protection valve, the pipe aperture and pressure acquisition frequency have great influence on the detection result of opening pressure and closing pressure for four-circuit protection valve. There is no relevant research, so it causes that detection results of different detection systems cannot be compared. On the basis of studying mechanical model and flow characteristics model of valve, dynamic process mathematical model and AMESim simulation model of open and shut detection system for four-circuit protection valve were established. Based on the experimental data, the effect of pipe aperture and sampling interval on detection results of open and shut characteristic for four-circuit protection valve was analyzed and verified. Results showed that the greater the intake orifice was, the shorter the opening pressure detection time was, the higher the detection efficiency was, the worse the stability of the data was. The greater the exhaust pipe aperture was, the greater the closing pressure was. The higher the data acquisition frequency was, the better the stability of the data was. When the effective flow area of intake orifice was 0.5mm2 and the system sampling interval was 0.001s, it can guarantee the detection stability and efficiency of opening pressure detection.