The key of computer-aided conceptual design is aimed at developing design model, which can be recognized by a computer. The paper presents a matrix representation method for kinematic schemes of mechanical products. The map mechanism from function to structure is founded by function and constraint matrixes of mechanism modules. And, the method provides a mathematical way of function decomposition. By using the model, an automatic synthesis of mechanical kinematic schemes can be brought, with a complex and novel scheme of mechanical kinematics being obtained.