Optimal allocation of reactive power compensation plays an important role in power system planning and design. However, as a non-linear, large scale combinatorial optimization problem, Conventional methods are not normally appropriate for it . A mathematical model is firstly presented in this paper for comprehensive optimal configuration in distribution feeders based on the analysis of engineering factors of reactive power compensation, whose objective is to minimize the annual expenditure involving the devices investment and the income of energy saving, and satisfy all sorts of operation，fixing and maintenance constrains. The control variables include the capacitor banks’ number and capacity of various compensation schemes. RARW-GA algorithm is adopted to solve this problem. The result of calculation and analysis of BenXi Steel group corporation power system shows that the proposed method is feasible and effective.