Abstract: Based on the method of fuzzy mathematics,the similarity of the projects completely built and to be built is studied,and eight factors affecting the cost of the project have been proposed.All the eigenfunctions and the approaches of the project completely built are calculated in this paper.According to the fabrication cost of the project being built,the fabrication cost of the project to be built can be determined accurately and rapidly.

Key words: fuzzy theory； cost of construction； project to be built；