This paper studies the impact of connecting power sources on the load modeling in a distribution network， finding that when the impact is not negligible， the composite induction motor load model will no longer be able to effectively describe the actual load characteristic. So a new load model is presented， which the authors choose to call the asynchronous generator plus ZIP model. The validity of this new load model is testified by simulation calculations. Furthermore， a composite load model for the induction motor and asynchronous generator plus ZIP model is presented.