Based on IEC 61850 and IEC 61970， a power grid modeling strategy is presented to make transition from concentrated modeling for main control center to reference substation model on demand by different control centers. Then it solves on-demand sharing of grid model， substations wiring diagram and measuring information between smart substations and control centers at all levels， and among control centers at all levels. The research result has been applied to Suzhous 500 kV Changshu smart substation and smart grid dispatching technology support system pilot projects.