As the market concept is gradually introduced into the power system, the attention and interaction on the demand side have been promoted to a new level, and the interests of participants in power system are gradually diversified. Load aggregator plays a more and more important role as an important coordinating organization between the power grid side and the user side. Based on the load classification, the definition of load aggregator is given, and the current situation of electricity market in China is reviewed and analyzed. The relationship between load aggregators and other market entities is analyzed, and the load aggregators are involved in the power supply. The key issues in the market are discussed in detail.