For increasing the determine efficiency of aerobic plate count in food,the electric impedance was used to determine aerobic plate count in 120 pasteurized milk samples and 114 pure water samples.Comparing with the method of the current national food hygiene standard of PRC,both methods had no significant difference.The conform rate of the results of both methods of pasteurized milk samples was 95 0%,that of pure water samples was 94 7%.False positive rate and false negative rate of pasteurized milk samples were 1 7% and 3 3%,that of pure water samples were 1 8% and 3 6% separately. The negative result of pasteurized milk and pure water samples needed 4 2 h and 14 5 h,the positive results of those needed 2 3 h and 11 3 h separately.The method can reduce the determining time from 48 to 14 5 h.