The participation of demand response（DR）in electricity market trading can enhance the optimal allocation of electricity resources

promote the DR programs implemented sustainably

improve the price mechanism of electricity market

and reduce the risk of electricity market operation. The DR approaches and mechanism under PJM electricity spot market are concluded. The process of DR participating in day-ahead and real-time electricity market

ancillary service market is described

and the principles related with DR approaches and mechanism in electricity spot market is also analyzed. Finally

based on the spot market in our country

the influence of DR mechanism to market transaction and dispatching is analyzed and suggestions for DR program implementation is proposed as well.