At present, the development of distribution network can’t meet the requirements of rapid economic development. The traditional single energy supply is difficult to meet the request, and distributed energy supply has a lot of advantages compared to it, particularly it's close to the end users, and they have been developed well and applied widely in recent years. This paper summarizes the features and current development of the distributed energy supply, and mainly describes the grid-connection model of distributed energy supply. Base on the mathematic grid-connection model of distributed power sources with different generation principles as well as that energy storage, the treatment of these models in distribution network power flow analysis is also presented.