Abstract: In order to solve the problem of pole disposition in controller designing with closed loop system, based on polynomial homotopic mapping and the corresponding zero loci, this article gave the definition of the homotopic fixed point, deducted and proved a pole disposition method based on the homotopic fixed point, which was equivalent to the pole disposition theorem original in the means of closed loop poles. The conclusion of the study can be applied in control system compensating design by root locus method effectively.