Before the construction of the deep pit foundation, we must choose a project. Although there aren't many projects to be chosen as usual, we often feel that it's a very complex and hard work. Actually there is no a mature and general model to use. In this paper, the author attempted to use the theory of fuzzy math to establish a former to select the best project, meanwhile provided two ways to solve how to quantify the qualitative targets and how to determine the weights of the targets. Finally they were confirmed to be useful and successful by a practical engineering application. It is worthily to popularize these scientific methods in construction and management in deep foundation pits.