Abstract: In order to evaluate the process capability in tobacco processing scientifically, taking moisture content control(MCC) during casing as an example, the course of tobacco processing was analyzed statistically based on the characteristics of steady-state process.The results showed that mathematical statistics, after the influences of the abnormal data were rejected, was capable of estimating the steady state of tobacco processing process, evaluating exactly the level of MCC during casing, describing and evaluating the process capability in steady state qualitatively and quantitatively.