In this paper, efficiency analysis and design of contactless electric power transfer systems working based on an inductive method are elaborated. Large leakage inductances of the systems are compensated to achieve resonance conditions for maximum efficiency. Considering the circuit models of a contactless system, the effects of different parameters including the compensating capacitors are analyzed for a specified frequency range and coupling coefficient. An algorithm is proposed to determine the optimal capacitors and resonance frequency. It is verified by experimental results. (C) 2012 Elsevier Ltd. All rights reserved.