Abstract: This paper is engaged in breaking performance experiments with three kinds of electrical contact materials-CuW80、CuW70 and CuWMgO, produced by different powder metallurgy technologies(impregnation method, presintered-tungsten-skeleton and then impregnation method and cold isostatic; pressing, presintered-tungsten-skeleton and then impregnation method). In a similar-model interrupter of high-voltage SF6 circult breaker, breaking tests were performed with a ramp-current testing circuits.Changes of microstructures of tested contacts were observed and weight loss of tested contacts before and after experiments were determined. The effect of microstructures of some contact materials on breaking performance were compared each other as well. It was found that CuW80 contact material produced by presintered-tungsten-skeleton and impregnation method has advantages over other contact materials in breaking performance and anti-arc-erosion.