Abstract: In order to deeply study the influencing factors of the prefabricated building cost, this paper constructs the index system of influencing factors in the construction stagebased on literature review and expert consultation, then analyzes the factors in the design stage, production stage, transportation stage, construction stage and environment. At the same time, considering the subjective and objective influences, the DEMATEL-FAHP-entropy weight method is adopted to evaluate the main factors affecting the cost of prefabricated construction. The relevant countermeasures and suggestions are put forward, which can provide reference for the cost management of prefabricated construction and the industry development.