1. School of Electrical Engineering, Southeast University, Nanjing 210096, China; 2. State Grid Suzhou Power Supply Company, Suzhou 215004, China

Demand response(DR)is one of the core technical functions of smart grid. Not only is it able to serve as a low-cost capacity resource in face of emergency, but also it can affect the pricing of electricity market which reduces price fluctuations. An overview on the participation of DR in marker environment is conducted and the technology of ancillary service provision for DR is discussed in detail. The operation mechanism, dispatch and control strategy and the potential of loads are described. Finally, based on the actual situation in China, existing obstacles to the implementation of DR in ancillary markets are analyzed and the huge potential and development trend of carrying out DR in ancillary markets are pointed out.