Abstract: Data Envelopment Analysis (DEA) is used in the paper to measure the validity of cooperative development in Beijing Tianjin Hebei and analyzes the reasons for the differences in the three areas. The research indicates the validity of cooperative development in Beijing Tianjin Hebei has not been achieved optimally, but overall efficiency of cooperative degree has been better and better. Cooperative degree between Beijing and Tianjin is greater than Hebei Province. Factor inputs from Beijing Tianjin Hebei contribute to maximum output but input and output ratio has not been achieved optimally. At last, based on the validity and orientation of cooperative development in Beijing Tianjin Hebei, the paper proposes corresponding suggestions.

Key words: the cooperative development in Beijing-Tianjin-Hebei, DEA, the validity evaluation