Air conditioning loads,characterized by their large amount,ease of adjustment,and minimal impact on users,are ideal demandside flexible resources. It’s necessary to research progress and directions of air conditioning load participation in ancillary service technologies from various perspectives. Firstly,the modeling techniques for individual and aggregated air conditioning resources are introduced.Then,the main challenges and technical methods for air conditioning participation in various ancillary services such as primary frequency regulation,secondary frequency regulation,and reserve capacity are analyzed. Air conditioning control technologies considering information security and reliability are discussed,and evaluation techniques for air conditioning load from the perspectives of grid interaction and user comfort are summarized. Finally,suggestions for further exploring the regulation potential of air conditioning load are proposed to promote the transformation of air conditioning load control technologies from theoretical research to practical applications.