Abstract: In recent years, a new technology of AGC frequency regulating for power grid by applying power resource at demand side is proposed in the United State. In this paper, concept of frequency regulation at demand side, load category and its characteristic applied in frequency regulation, key technology requirements of each link needed in frequency regulation and commercial modes are systematically analyzed. In the end, promotion suggestions on frequency regulation at demand side are proposed by combining with the development of power ancillary service market in China.