A system for integratedly testing damping performance of a hydro-pneumatic suspension vehicle, including a testing platform and a testing device. The testing device includes a sensor module, a data acquiring and processing module and a testing software. A method for integratedly testing damping performance of a hydro-pneumatic suspension vehicle is also provided. A calculation is performed by a testing software to optimize a sensor configuration. A signal is acquired and transmitted by the sensor module. The signal is acquired and processed by a data acquiring and processing module, and displayed and analyzed by the testing software.