Implementing business processes reengineering (BPR) may adopt two main ways: radical-revolution way and gradual-changing one. Choosing critical business processes is a key step for implementation of BPR by gradual - changing way. For most of Chinese enterprise, gradual-changing way is better one. Applying multiple objective-decision theory, this paper sets up a evaluating indexes system of business processes of BPR. It is designed by three aspects: the urgency principle, superiority principle and the importance principle. Then it decides the weight of each index in this system by the method of minimum-square of weights and makes each index into non-dimensional processing respectively according to different type of the index. Finally, all business processes in a company are in comprehensive sequence through the model of decision-matrix, then the critical business processes can be choose according to this sequence.
