The invention discloses a power-system economic dispatching method considering power grid topology optimization. A power-system dispatching model using active power of conventional generator sets and output component states of the power grid as decision making factors is provided by incorporating the power grid topology optimization into a power-system economic dispatching model and considering the power grid topology connectivity conditions. Topological connectivity is constrained based on the minimum cutset concept in graph theory so as to judge system topological connectivity. The provided model is solved by combination of genetic algorithm and linear programming primal-dual path following interior algorithm. Conventional generator sets and power grid topology can be preset, economical efficiency of power grid operation is improved on the premise of guaranteeing safety of power grid operation, balance capacity of load power of system generation is improved, renewable energy power generation can be accepted within a larger range, abandonment of renewable energy power generation or load shedding is effectively alleviated, and technical support is provided for intelligent development for power system dispatching.