In this paper, sensor ring for antilock brake system was studied using the 400 series ferrite stainless steel powder. Because of more excellent corrosion resistance and mechanical characteristics than iron, sensor ring has been manufactured by P/M(Powder Metallurgy) method 400 series ferrite stainless steel. the results are following. 1, Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 2. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.