The LCC compensated wireless power transfer (WPT) systems contain non-negligible harmonics, which affects its performances including the zero voltage switching (ZVS) characteristics. With fundamental harmonic approximation (FHA) model, the system performances cannot be described accurately. In this paper, a harmonic-considered time domain model of LCC compensated WPT systems is proposed. The proposed time domain model combines the FHA model and harmonic model to get high accuracy for system behavior describing. With the proposed time domain model, the system parameters can be optimized for ZVS realization under phase shift control. A 500 W prototype is built; the experimental results verify the accuracy of the proposed time domain model and the effectiveness of the ZVS optimization design.