Abstract: Analytic hierarchy process (AHP) has some obviously limitations because pairwise comparison process is complicated and meets the consistency hard with the increasing in the number of factors, which weaken the applicability of AHP a lot. In order to overcome these limitations, authors introduced gray correlation model and combined the two methods with scales of transformation conversion of gray correlation coefficient matrix and abandoning pairwise comparison, then proposed an improved analytic hierarchy process (IAHP). The proposed IAHP overcomes the shortcomings of AHP and increases the applicability of AHP. Based on the IAHP, a comprehensive evaluation system for Langfang Suning plaza foundation engineering was set up, and the risks of the excavation process were assessed. Finally, extreme high degree risks were determined via quantities of the combination weight, which will provide technical guidance for engineering construction smoothly.