In order to analyze the vibration caused by the impact between warehouse rack and wheeled mobile logistics robot(WMLR) during cargo transportation, equivalent nonlinear springdamping model is used to describe the impact process between the rack and WMLR, and the multibody dynamic model of WMLR as well as the warehouse rack is established with Lagrangian Multiplier Method. The result of differentialalgebraic equation obtained from multibody dynamic model is calculated by using Newmark difference method in terms of several typical work cases of the rack. A virtual prototype of WMLR is also established in ADMAS, and the dynamic response of the rack during transportation is analyzed and compared with the results of analytical model. The results provide significant instructions for stability control of WMLR.