Abstract: Formulas of relation between magnetic coupling resonant wireless power transmission efficiency and offset angle of coil and transmission distance were derived according to magnetic coupled resonant wireless power transmission model with two coils. Effect of transmission distance and offset angle on transmission efficiency were studied, and conclusions were obtained as follows: as transmission distance increases, impact of offset angle on wireless transmission efficiency becomes smaller and smaller; When offset angle is small, its effect on transmission efficiency is not significant; when offset angle is greater than 75°, the transmission efficiency decreases sharply with increase of offset angle; as the transmission distance increases, decreasing trend of wireless power transmission efficiency is more and more gentle.Correctness of theoretical analysis was verified by Matlab simulation and experiment.