In order to improve the precision of machining and efficiency of cathode movement planning,the shaping law of tool-cathode for precision electrochemical contour evolution machining of integral impeller has been studied,and the mathematical model was established,the offset curves along the normal direction of vane transversal in fitting surface of impeller blade profile has been used to design the movement trajectory of contour evolution,cathode velocity along the trajectory have been designed according to the mathematical model.Then,the thickness of electrochemical solution could be controlled.The results of experiment shows that using the mathematical model and the designing method of movement planning can improve the productivity of movement planning in electrochemical contour evolution machining integral impeller.