The invention relates to a power system grid structure reconfiguration and optimization method based on fuzzy chance constraints, which belongs to the field of power system security defense and restoration control. The power system grid structure reconfiguration and optimization method comprises a grid structure reconfiguration and optimization model establishing module and a grid structure reconfiguration and optimization algorithm module. The power system grid structure reconfiguration and optimization method adopts triangular fuzzy variables for representing line operation time and restoration reliability, defines an restoration reliability index for evaluating performance of a target grid structure, considers unit start-up time limit, establishes a grid structure reconfiguration and optimization model based on fuzzy chance constraints under the framework of the fuzzy chance constraints, adopts a solution method of combining fuzzy simulation, a crossed particle swarm optimization algorithm and a Dijkstra algorithm, optimizes and determines unit start-up sequence, and reconfigures a restoration grid structure with shortest reconfiguration time and highest reliability. According to the power system grid structure reconfiguration and optimization method based on fuzzy chance constraints, the fuzziness of operation time and restoration reliability when the line is put into operation at the grid structure reconfiguration stage is reasonably considered, the optimized and determined optimal grid structure reconfiguration scheme takes both system reconfiguration speed and safety requirements into account, and the power system grid structure reconfiguration and optimization method has more practical significance.