Aimed at a mobile robot composed of a two-wheel differentially driven AGV (automatic guided vehicle) and a manipulator with 6 degrees of freedom(DOFs), the dynamics models of the manipulator and the AGV were established respectively by using Newton-Euler method. Then two models were combined to analyze the interplay of the AGV’s movement and the manipulator joint movement in moving manipulation. An example was given to explain the interplay result of two parts in detail, in the process of moving manipulation, manipulator joint force and moment were impacted by the base movement of AGV, at the same time, the manipulator joint movement brought the load varying of AGV which might change the moving state of AGV. Some important rules about this kind of robot relative to a single AGV and a single manipulator in designing and controlling were put forward. The dynamics models provided a foundation for designing and controlling this kind of mobile manipulator.