The identification of the mutual inductance and load voltage is important to the control and optimization of the wireless power transfer (WPT) systems. The paper proposes a novel identification method based on the voltage transients. Connecting an equivalent sensor inductor in the primary resonant tank, the voltage transient values caused by the rising and falling edges of the inverter output voltage and the rectifier input voltage are relevant to the mutual inductance and load voltage. By detecting the voltage transient amplitudes, the mutual inductance and load voltage can be identified directly.