Abstract: Traditionally function-oriented modeling and object-oriented modeling are the two major modeing techniques The major advantages of them are the implement of system function, but the abilities to analyze and evaluate in it are too weak. The modeling technology based on Petri Nets advanced in this paper is a good simulation to the system realizing, it could describe the system structure not only, and can be used to analyze the various characteristics of information system by the tools of figuring and mathematics in GNT.

Key words: Petri Nets, information system model, resources constraint