Theoretically, magnetic resonance wireless power transmission can achieve high efficiency. However, due to the influence of various media, a large deviation exists between the measured efficiency and the theoretical efficiency. A magnetic resonant wireless power transmission system in non-ferromagnetic medium is proposed based on the equivalent circuit model. The influences of different media on the coil impedance and resonance frequency are analyzed by calculation and simulation, and the results of calculation and simulation are in good agreement. The design steps of the high efficiency system in the medium are proposed, and the simulation results show that the efficiency can be improved by more than 30% after optimization.