Abstract: An information system operation process complexity model based on complexity theory is proposed. Five metrics included operation complexity, parameter complexity, context complexity, interaction complexity, and parallel complexity are defined, The formal definition and calculation method of metrics are presented. Furthermore, the normalization function is proposed, it can process metrical data and compare the single metric influence in total complexity. The model validation is verified by constructing an Email service system. This model can be not only used to measure the complexity degree of information system operation process and search operation hotspot, but also to evaluate and optimize the operation process in order to improve the operation quality and efficiency.

Key words: operation process, complexity model, singleton