Abstract: Pseudospark switch is a kind of low pressure pulsed discharge switch which works at the left hand of the Paschen's curve, ignites in the hollow cathode and presents dispersive discharge channel. It has the advantages of large current capacity, high repetition rate, wide working range, long lifetime, small jitter and low erosion rate. In this paper, a double-gap and multi-channel pseudospark switch is developed, which is semi-sealed with ceramic and metal. The working gas is helium, and the trigger unit is of the charge injection structure based on BaTiO₃ with high dielectric constant. The discharge characteristics and operation modes of the trigger unit under different pulses are studied, and the effects of gas pressure, pulse rising edge and energy on the charge injection characteristics of the trigger unit, triggering delay and anode voltage dropping rate are studied. Besides, the multi-channel synchronous triggering characteristics of the switch are analyzed according to the electrode erosion morphology, and the current quenching phenomenon is discussed according to discharge waveforms. The experimental results show that there are two operation modes of the trigger unit discharge, namely, pulsed corona and flashover along the surface; high pressure and high energy trigger pulse are conducive to reducing the triggering delay, jitter and anode voltage dropping time. The pulse with fast rising edge is beneficial to reducing the jitter, and anode voltage has no obvious influence on delay and jitter. The switch can realize multi-channel synchronous triggering and conduction, and there are two quenching forms under the condition of small current.