There are two key problems in the manufacture process of impeller, one is the collision of tool and blade, the other is gnawed-cutting arisen by non-uniform change of the cutter axis. UG software was used to solve those problems. Tool tip position was solved by UG. The control algorithm of collision-free cutter-axis was described and applied. The cutter-axis vector was optimized by quaternary linear interpolation method to make normal vector of blade changing continuous, so. These methods were synthetically used in the manufacture experiment. The impeller produced by it was qualified. It indicated that the method of tool vector control was feasible.