In order to resolve the critical chain project management issues which affect the overall interests of the enterprises,this paper puts forward the concept of sub critical chain group.This concept minimizes sub project sum as the goal in the multi project.Based on single critical chain project management,the conflicts in priority allocation of resources projects were analyzed,and the distribution rules which limit the time for a project to reach the minimum value.At the same time,draw a combination scheme which maximizes the overall interests of the enterprise through the rational allocation of project priorities,and this scheme is verified by practical examples.