The invention relates to a demand response system oriented to building energy optimizing operation, and belongs to a power utilization service technology. The demand response system comprises a decentralized control layer, a regional coordination layer and an optimal scheduling layer, wherein a controller of the decentralized control layer is used for acquiring information, uploading the controller information to a building management system, uploading the controller information to a regional resource coordinator of the regional coordination layer through the building management system, and updating the controller information to an acquisition server of the optimal scheduling layer; an application server of the optimal scheduling layer interacts with a load control system and sends a demand response load vacancy command to the regional resource coordinator, and the regional resource coordinator decomposes the demand response load vacancy command finely to generate a demand response load capacity level command and sends the demand response load capacity level command to the building management system and the controller in sequence. By adopting the system, itemized energy utilization information data acquisition and fine load control of a building can be realized, passive control of the conventional load is turned into active response, and the power grid peak load demand is lowered.