A novel three joints underactuated manipulator has been proposed in this paper. Firstly, the structure features of the manipulator are analyzed. Then, the kinematic model with triangular structure can be converted into the chained form through appropriate design for structural and kinematical parameters. Finally, the result of simulation for three joints underactuated manipulator indicates that the joints angles can be move the desired value by input velocity control of two motors. It is concluded that it is feasible to design controllable manipulator with nonholonomic theory.