The docking mechanical design and automatic generation of dynamics for a novel reconfigurable robot was studied. A novel unit module of the mobile modular reconfigurable robot (M 2 rBot) with twelve connection ways was firstly presented, which would enable the multiple-module robot to revolute with multi-directional rotational degree of freedom. The unit module was cubic structure with one active and three passive connection surfaces with compact structure and flexible motion. By using a new type of transmission groove with a sine acceleration curve and a pin-hole connection, the docking mechanism design was also accomplished. The mathematical transformation description table for describing the double modules’ space pose transformation (DMSPT) was then established, and the forward kinematics equations of the multi-branched chain robot were automatically derived. The dynamic equations of the M 2 rBot were also automatically generated in two steps by using geometrical formulations and the recursive Newton-Euler method, which was based on the global matrix description. And the algorithm of automatic generation of motion equations was also given based on DMSPT. Finally, taking the six-module configuration with two branches as an example, the calculation and simulation analyses of automatical generation of motion equation demonstrated the feasibility and validity of the proposed method. The simulation results will be directly used in the design of the adaptive controller applied to the different configurations for the multi-branched chain robot.