To deal with the problems of low voltage with heavy load while high voltage with light load in rural distribution networks, an approach of improving the voltage performance by utilizing the nature adaptability is proposed, in which, neither communication nor control is needed. The optimization planning model is set up, in which, the benefit in the planning period is introduced as the index. The benefit of loss reduction, the cost of fixed capacitor arrangement, conductor expanding and cable replacement are considered in the planning. A typical example is given to illustrate the proposed approach, the results of which show its feasibility and effectiveness.