This paper analyses the production benefit of renting equip-ment in the construction enterprise qualitatively and quantitative by adopt-ing system inethod.According to dynamic program principle, the paper establishes the recurrence formula of mathematical model to solve the total expense of renting equip-ment. This formula is used to make a series of cal-culation by living example,therefore it obtains the optimal plan of renting equipment in a practical engineering.This method has better use value.