In order to study effects of dynamic load change on whole capability of mine vehicle, a hydropneumatic suspension system in operating conditions were tested and analyzed. Four accelerometers were fixed to the upsideunderside of h ydropneumatic cylinder, and two pressure sensors were fixed to the piston cavi t y, respectively. The displacement curves were obtained by accelerometer and fast Fourier transform (FFT)direct digital integration (DDI), and the load fluctua t ion of the vehicle were obtained through pressure sensors. The displacement char acteristics of actual hydropneumatic suspension system were tested. The result s show that stiffness of suspension system has obviously nonlinear features. Exci ted randomly by road surfaces, change amplitude of stiffness with the excitation load is moderate, and change of bodywork’s height with the load is small.