Multiple mode production process is a kind of production process which has many stable operating points. The transitional mode is the transient process which links up two stable operating points. This transitional mode has complex dynamic characteristics. According to the characteristics of transit ional mode itself, based on the difference principal component analysis method, this thesis puts forward an operation performance evaluation method for evaluating transitional mode of multiple mode production processes. This method can effectively evaluate the running state of transitional mode. It can help to improve the efficiency of the production process and ensure production safety. It is important to improve the economic benefits of production process.