According to the power system protection system modeling, IEC 61970 standard and IEC 61850 standard for the protection modeling method are analyzed. According to the deficiency of IEC 61970 standard for protection model modeling method, combining with the advantages of IEC 61850 standard secondary system model, this paper extends the IEC 61970 standard protection model; for the protection functions in protection system, it extends the protection module class for protection function description, which can correspond with the IEC 61850 standard logical node; for the protection measuring, it describes the protection measurement modeling method and modeling position, and takes the protect module as protection measurement father resources; for the protection fixed value, two types of measuring methods are added to describe the modeling method and protection measure. According to the expansion of IEC 61970 standard protection model, the actual modeling application is described.