Abstract: According to the physical design and electrical parameters of the 300 kA single induction cavity developed for linear transformer drivers, a more detailed circuit model for single induction cavity has been proposed, in consideration of gas spark switch channel resistance, electromagnetic-coupling effect among discharge bricks, hysteresis losses and saturation characteristics of cores, and secondary power transmission. Experimental results have verified the effectiveness of the model. The simulation results for cavity working normally or with single brick in self-discharge states agree well with the waveforms acquired by experiment. It indicates that the circuit model is capable of simulating operating characteristics of induction cavity even though there are devices in abnormal states in it.