The magnetic pinch mechanism is a key issue to study the arc ignition mechanims and its response properties of a liquid metal current limiter.The pinch regularities and charactertics of liquid meta（lLM）in the current limiter are obtained for the first time in this paper.An experimental device with transparent viewing window and a single spacer is designed for the study of the LM’s magnetic pinch behaviors.The short circuit current is supplied by a LC oscillating test circuit.The experimental study on arc behavior and its evolution characteristics is conducted.It indicates that the whole process begins with the direct separation of LM from the channel wall and it finally pinches to ignite the arc at both ends of the channel.Moreover

a 3-D numerical model is built allowing for the effects of the LM-channel contact characters and the channel wall’s surface topography

which help to reveal the LM’s pinch mechanism.