In order to solve the problem of the lacking of multi-factor quantitative analysis and importance evaluation in the topology optimization of far-offshore wind power grid-connected through VSC-HVDC, the topology optimization is carried out based on the comprehensive benefit evaluation. Specifically, a multi-index evaluation system covering three factors of economy, utilization ratio and reliability is constructed and the calculation models of each index are given. An improved AHP-entropy weight method is proposed to determine multi-index weight and TOPSIS method is used to choose the best option. In the example, the comprehensive benefit of point-to-point, ring and star topology schemes of Rudong offshore wind power project is evaluated and compared, and the sensitivity analysis of reliability weight and preventive maintenance rate is carried out to verify the validity of the proposed model.