The previous data envelopment analysis(DEA) can only be used to measure relative efficiencies of decision making units(DMUs) in either input orientation or output orientation, so it is considered to be traditional DEA in this paper. As the result, it is unable to reflect totally the performance of DMUs in the input output process. On the basis of bi objective programming,this paper develops input and output oriented DEA so as to assess relative efficiencies of DMUs in both input and output orientation,and further discusses the relative eficiency of DMUs