Gallium Arsenide Photoconductive Semiconductor Switch (GaAs-PCSS) has outstanding features, such as, fast response, high repetition, low jitter and high-power capacity. Multi-channel design can effectively reduce the damage from high current in nonlinear mode and improve switch’s lifetime. In this paper, on the solid-state pulse forming line experimental platform, multiple GaAs-PCSSs are connected in parallel as one switch through a special fixture, and different trigger signals are applied to each of them, in order to study the necessary conditions for GaAs-PCSS multi-channel synchronous conduction. The results show that, firstly, by the same trigger signals, the on-current is successfully divided into 4 GaAs-PCSS channels; secondly, by different trigger signals, the delay time difference and trigger energy difference must be lower than 1 ns and 20 μJ respectively, if an effective current diversion is expected; thirdly, split and integrated multi-channel GaAs-PCSS structures are designed, and the integrated 20-channel GaAs-PCSS was slightly damaged after 7 000 shots.