Abstract: Reactive power optimization for electric power system always plays an important role of researching on security operation of power system. As to the demand for reactive power optimization in distribution network, this paper puts forward a practical method of reactive power optimization. By using of this method, the data exported by Power System Analysis Software Package (PSASP) is used, the minimization of losses of active power for entire network is the objective, and optimization is realized by genetic algorithm optimization toolbox in MATLAB. In the end, the reactive power optimization of certain distribution network according to the actual data is implemented by this method. The results show that the method can effectively reduce the network losses and can improve its operating conditions, which verifies its validity.