To evaluate the strategy of reliability enhancement for an existing industrial power system , the Benefit-Cost ratio of all possible improvement scenarios have to be investigated . This thesis presents a quantitative and systematic method to solve the Benefit-Cost ratio of network restructure for reliability enhancement . This method can provide a simple and effective tool for planning reliability improvement in the industry power systems. Up to now , many methodologies have been developed to solve the service reliability for distribution power systems . In this thesis , the reliability indices of industrial power systems are calculated to evaluate the service quality . According to the result of reliability analysis and the corresponding cost of loss of load for each load bus , the annual power outage cost is derived for each scenario of system restructure. By integrating the power outage cost and the corresponding investment cost , the optimal reliability enhancement is determined by the best strategy with the Benefit-Cost ratio.