Arc discharge behavior is one of the key factors on current limiting characteristics of liquid metal current limiter based on magnetic pinch effect. A single separator experimental device with transparent viewing window is designed for the study of arc discharge characteristics. The short circuit current is simulated by LC oscillating test circuit. The experimental study on arc behavior and its evolution characteristics of different channel materials is finished. The experimental results indicate that the arc evolution can be classified into four stages including arc ignition

arc elongation

arc constriction and arc extinction. The arc behavior and current limiting characteristic are influenced by the strong pressure generated by ablation of channel materials. The arc will extinguish before current zero if the pressure is too large inside the enclosure. This phenomenon is not conducive to the current limiting of LMCL.Compared to quartz glass

plexi glass and GPO-3 can accelerate the development of arc and improve the arc voltage

but the arc ablation of them seriously affect the lifetime of LMCL. It is necessary to explore new thermo materials.