A three-layer modeling method from collection points to device containers then to industrial applications is developed to access more and more new-type device data to the power monitoring system. Firstly， collection point models in different collection types are set up. Then， the incidence relations between relative devices and collection points are set up. Finally， the industrial model of data according to industrial application requirements are set up and the unification with the common information model（CIM） is realized. The efficiency and security of the data model is ensured using a special storage and checkout method. With this method， there is no need of model modification when accessing new-type device data for the power monitoring system of new energy sources， improving the adaptability and expansibility of the system.