In order to speed up the development of vehicle active safety technology in China, C-NCAP plans to add AEB and AEB VRU system as assessment items in 2018. With the purpose of studying the assessment protocol of AEB system, we have carried out 400,000 km road information collection and then we acquired the statistics of the operation conditions of dangerous situations. Combined with the traffic accident data collected by CIDAS, we found that the dangerous situations that we usually met were mainly three types,that was CCRs, CCRm and CCRb.Based on what we mentioned above,we analyzed the three kinds of working conditions and gave the corresponding evaluation method.In addition,combined with the actual situation of China, we added two tests of error function.And then we took the actual road experiment of many models of vehicles.We made a count on twenty vehicles which were domestic sold from joint venture and autonomous vehicles with the purpose of analyzing the deceleration of vehicles that were domestic sold when a full braking was taken.What’s more,we have analyzed 40 traffic accidents about car to car crash aiming at test scenario, testing speed point and weight distribution.Then we formulated the draft version of assessment protocol. Through carrying out 4 vehicles’ AEB tests, we found the assessment protocol could reflect the system performance well, and at the same time the test result could give support for optimizing our assessment performance. Besides,the conclusion of this study can supply reference for making C-NCAP AEB system final assessment protocol.