Abstract: To obtain the Jacobian matrix of parallel robot,based on the velocity relationship between two points on the mobile platform,a new expression to construct the Jacobian matrix of parallel robot by its branched chains is deduced.This method can be used for the automatic generation of Jacobian matrix of paral- lel robot or hybrid robot,the multiplication in the new expression is less than that in the Jacobian matrix de- duced by Monsarrat and Gosselin in literature five while the flexible linkages are omitted.The correctness of the presented method is validated by analyzing the plane 5R parallel robot.