The design and implementation of the high frequency power supply, which offers a high frequency current to the primary winding, are of great importance in magnetic coupled Wireless Power Transfer (WPT) system. But the power supply, used in conventional WPT system, is comprised of rectifier and high frequency inverter, has the shortcoming of comparatively complicated structure and control. So, this paper proposes a novel single-stage AC-AC resonant converter. The proposed converter, converting the line source directly into high frequency source applied to WPT system via one stage conversion, has the advantages of less power elements and higher power factor. Experiments are carried out to verify the effectiveness of the proposed converter utilized in the WPT system with SS topology.