The dynamic response characteristics of PCB spark gaps under transient pulses are investigated using the field and circuit synergistic method. Firstly, the spark gap discharge tube is taken as the research object, and its measurement system under TLP pulses of different voltage levels is built, and its response voltage and current characteristics are obtained. A three-dimensional full-wave model of the measurement structure containing a spark PCB gap is built in CST, in which a SPICE netlist is used to describe the time-varying arc-resistance model when the gap breaks down, and then a voltage-controlled switch is used to control the startup of the Toepler’s time-varying arc-resistance model in the field-circuit co-simulation of CST to solve the problem of the time lag of the spark gap breakdown. The simulation results of the response voltage and current are consistent with the actual measurements, and the time-dependent distribution of the surface current on the PCB is obtained by the field-circuit co-simulation. Finally, the proposed field-circuit cooperative modeling method is successfully applied to the simulation of spark gap discharge on PCBs, and the results are in good agreement with the tests.