The existing evaluation models of enterprise informatization level are mostly static evaluation model. And they can’t meet the need of dynamic evaluation of enterprise informatization level. According to the principle of priority information, this paper proposes a new method to determine time series weights based on matrix norm. By using the driving principle of the difference, this paper gives a determination of index weights. And based on time series weights and determination of index weights, the paper establishes a dynamic evaluation model of enterprise informatization level, and gives the calculation steps. Through the case study, this paper tests the validity of the model.