To achieve high transmission efficiency during the charging process of wireless power transmission systems, the relative position between the primary coil and the secondary coil in the magnetic coupler needs to be kept as constant as possible. However, the offset of the coupler coil is inevitable in practical applications. Therefore, this article analyzes the additional compensation topology of resonant converters, the reasonable selection strategy of resonant parameters, and the influence of parasitic parameters on parameter design. A composite resonant coupler considering the influence of parasitic parameters has been proposed, which has higher anti offset capability. This coupler integrates traditional BP couplers and a simple series series topology structure, thus achieving numerical decoupling of the primary and secondary mutual inductance of the magnetic coupler. On the basis of a composite resonant coupler, a field circuit coupling model of an anti offset system is constructed, and the influence of parasitic parameters on the anti coil offset ability, constant voltage output ability, and overcurrent protection ability of the magnetic coupler is analyzed. This study provides a theoretical basis for further improving the system's anti offset capability.