Abstract: The genetic algorithm is an optimization method based on the concept of natural selection.Aiming at the long-term problem of reactive power optimization planning in power system,an algorithm of reactive power optimization planning based on genetic algorithm was presented,which remedied the defects such as no considering the demands of reactive power compensation under system’s minimum load mode and fault condition as well as the different demands of reactive power compensation because of load change at different years.The result showed that the algorithm is reasonable and effective.