Abstract: In order to improve the adaptability and validity of reactive power optimization, the load uncertainties were accounted in this paper, and load coefficient and power factor were taken as fuzzy number. In this application, after load data analyzed, three load levels were given. The basis of known node voltage and sending end power of the feeder, and the main line was determined after the power flow analysis. According to the optimum of power losses at the maximum load to determine the var compensation positions, and then the upper and lower limits of reactive power compensation capacity was calculated for the least accounting expenditure cost. The method proposed was applied to a real grid example of Keshike Teng County, Chifeng, Inner Mongolia for illustration. By calculation, analysis and comparison, the results show that the loss is significantly reduced for the method when the loads are changed, and the method can adapt to the needs of reactive power optimization of the rural power network.