Offshore wind power has tremendous promise. Transmission of offshore wind power is more expensive and more challenging than that of onshore wind power. Therefore, choosing a cost-effective ands efficient wind power transmission system is essential for planning offshore wind farms. In this work, primary economic and technical factors are comprehensively considered while analyzing high-voltage alternating current and voltage source converter-based high-voltage direct current systems, which are in use primarily, and the multi-criteria decision-making technique is applied to choose the optimum system. Firstly, a selection index system is established through analyzing economic and technical indicators for systems. Secondly, based on the above analysis, the improved analytic hierarchy process method and the criteria importance through intercriteria correlation method are employed for decision-making. They calculated the subjective weights and objective weights, respectively, and then, the above weights were fused by ideal solution, yielding comprehensive decision weights. This can reduce the arbitrariness of subjective scoring and solve the problem that objective scoring does not pay attention to the actual relationship between indicators. Finally, the technique for order preference by similarity to ideal solution (TOPSIS) method is used to determine the optimal selection of offshore wind power transmission systems at different offshore distances. The selection results show that the proposed method can effectively realize the power transmission system selection of an offshore wind farm.