At present, the substation SCD model mainly aims at the modeling of primary equipment and secondary equipment, and the description of auxiliary equipment and substation area model is missing. According to the characteristics of equipment monitoring of the new generation centralized control station, the description of auxiliary equipment model and area model needs to be added to the original IEC61850 standard. In the first mock exam station, the current business requirements of centralized control station are analyzed. A unified model structure of master station is designed. Based on the definition of IEC61850 standard, a method and example of extending auxiliary device model and regional model are given. The proposed auxiliary equipment and area modeling method based on IEC61850 standard can make up for the shortcomings of the original standard, support the equipment monitoring of the new generation centralized control station and realize rich application functions.