This paper presents a modular robot called RBT-6T/S01SM. This robot composed of 6 basic modules which could composed 5 kinds of robot. Each module owns one rotational degree of freedom. The total combined robot RBT-6T/S01SM features an easy-to-build mechanical structure. A formulation of this robot is educed based on Denevit and Hartenberg in this paper.The kinematics is studied and inverse kinematics is obtained based on algebraic method. The kinematics simulation of RBT-6T/S01SM is presented based on Matlab. The effectiveness of kinematics equations is verified by the simulation results.