Online monitoring is the precondition to achieve state maintenance and lifecycle management in power grid. Also, effective data transform model is the basis of online monitoring. We propose a data transform model for intelligent substation and PMS device online monitoring based on analyzing Standards of intelligent substation and State Grid. The PMS data are classified and compared with data model of IEC 61850 Standard. With methods of tag mapping and ID index we achieve the data conversion between intelligent substation and PMS.