Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover switch is carried out in vacuum condition with pulsed voltage. The switch consists of flat electrodes and columned insulator. A single/double harmonic, with wavelength λ of 1064/532 nm, Q-switched Nd: YAG laser is applied to trigger the switch. The results of experiment show that switch delay time and jitter time decrease with increase of pulsed voltage and laser energy density. Based on the waveforms of switch voltage and switch current, the circuit model of laser-trigger flashover switch is set up by circuit method in the paper. The parameters of the circuit model are calculated through the waveforms of the experiment, and the waveforms of switch voltage and switch current are obtain through circuit simulation. The simulation waveforms of the switch model are consistent with the waveforms of the experiment.