Abstract: This paper put forward a rapid method detecting total bacterial count in food. The CO2 produced by bacterial have the positive proportion to the total bacterial count. Therefore, the original total bacterial count can be calculated by detecting the total react heat quantity between CO2 and alkali using DSC. In this experiment the rotate speed on level 2 and the flow velocity on 4.0ml/min as the cultivate condition were choosed, and a “caloricity- total bacterial count”curve was established. The results showed that the method was reasonable.