In order to improve the safety and stability of hydraulic expander products, a hydraulic loading test-bed based on PLC is designed. The test-bed can perform fatigue and overload tests on the expander products, the control system of the test-bed uses the HMI to set parameters and display data, and a closed-loop negative feedback system is used to the control loading pressure in PID regulation with PLC and sensors. The test data shows that expander can work stably under the test requirement range by using the test-bed which can give accurate load regulation. Test-bed not only provide basis for product design,development and improvement, but also has a certain guiding significance for the development of constant loading test equipment.