Aiming to share the information, knowledge and optimizing resource via collaborating with multiple external partners across their supply chains, the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward. While there is Considerable pressure to improve the operation of MECORP system, their inherent complexity can make modelling a MECORP system a difficult task. Yet there could be considerable benefits in designing MECORP taking into account the operation of the system. In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system. The methodology called process-oriented decision model (PODM) is presented in the paper. This uses an abstracted network to model MECORP system. The MECORP system supported by PODM, can effective optimize the manifold resource, coordinate the relationship of multiple partners and assist decision. Finally, an industry example of MECORP system is described to illustrate the application of PODM.