The paper proposed a method for determining the current ratio of coils that maximizes coil-to-coil power efficiency in a wireless power transfer system with a double-sided LCC topology. In the previous study, when the rated input power and rated load were determined, the input and output currents were determined in the double-sided LCC topology, but the currents of the coils could be freely determined. In this paper, the ratio of parallel capacitors on the transmitting and receiving sides was determined to minimize losses in the coils in the double-sided LCC topology, and through this, the ratio of the current of the transmitting coil to the current of the receiving coil was determined. The current ratio of the proposed coils was arranged through the formula analysis, and it was proved through simulation that the coil-to-coil efficiency of the wireless power transfer system designed through the proposed method has a maximum value.