Abstract: Modern enterprise reorganization and CIMS resource scheduling are typical optimization problems of resource combination. A new modeling method, called expanded parameter petri net-EPPN, for this problem of resource combinatorial optimization is , presented in this paper. Expanded parameters are introduced into EPPN by extending the definitions of color Petri net, time Petri net, and so on. In this way, EPPN has higher ability to model and evaluate the process of task execution. Moreover, through expanding decision level Petri net model, EPPN can integrate any optimal strategy and algorithm to select optimal scheme of resource combination effectively and flexibly. The effectiveness of this method is proved by the results of the samples.