Topology evolvement is not considered in OPA model and its variants. To deal with this problem， an improved OPAmodel considering topology evolvement of power grid is proposed. This model integrates the basic OPA model with temporaland spatial evolving network model for power grid topology. The OPA model is used to simulate the evolvements such as loadincrease， transmission line update and cascading failures. While the temporal and spatial evolving network model is used tosimulate the evolvement of topology. Influences of different evolving parameters on the blackouts are studied. Simulationresults indicate that Northern China power grid has a larger probability for small-scale blackouts and a smaller probability forlarge-scale blackouts than Western America power grid. This model provides a way to study the long-term effects of differentplanning schemes and parameters for power grid.