Abstract: One of the basic problems of problem solving in AI is how to make use of the heuristic information of the problem domain to reduce the computational complexity.This paper presents an AHP method of constructing the estimate function in the computer structure layout design.By calculating the value of the estimate function and adopting the best first searching strategy,the combination explosion in spatial layout design can be avoided and satisfying solutions can be reached in the limit of space and time.The method presented can not only be applied to spatial layout design,but also be easily extended to general design problems and is therefore of important applicable value.