Nanocrystalline CuCr alloys with a relative density of above 98% can be prepared by high energy ball milling and hot pressing technique. The grain size of nanocrystalline CuCr alloy is less than 50 nm. The vacuum arc instability and chopping current of nanocrystalline CuCr materials were studied in an artificial circuit. The results show that the vacuum arc of nanocrystalline CuCr is more stable than that of conventional materials, the chopping current is 17%-35 % of that of conventional alloys.