Ride comfort is one of the main using performance items and competitiveness index of the automobile. This paper carries out shock absorption performance experiment for a certain light truck cab suspension system to study the shock attenuation rate of the four suspension points of the cab when it is under no-load and full-load status running with speed of respectively 40，50，60，70，80 km /h, as well as under the idle speed status. The result shows that the shock attenuation rates of the front cab suspension points under various conditions are low. And the shock attenuation rate of the back cab suspension points at Z direction is low. Front and back cab suspension points have no attenuation to low frequency shock. It is suggested that the cab suspension rigidity needs to be re-matched.