When the car radiator is designed by axiomatic design, the existence of the coupling function is widespreaded. Scholars put forward using artificial immune system to solve the coupled function sets. Based on the shortcomings of these algorithms in measuring antibody, this article puts forward the new measures: coupling function centralize degree, and gives the appropriate formula. At the same time, the gene optimization method is introduced to antibody generation algorithm. Thr experiments of auto engine oil radiator in Yinlun CO., LTD show that the new algorithm has higher efficiency.