We introduce a systematic method that combines process-oriented design and abstract systems to specify multiprocess system using Event B. As far as specification is concerned, the proposed method guides the user to describe his/her system by considering both process-oriented view and event B style of specification. With regard to mechanization, the method enforces the conjoined use of both theorem proving technique and model checking technique with the associated tools: AtelierB and ProB. This method makes it easy the specification in Event B of multi-process systems and it also fasters the correctness proof. Our proposal is illustrated with a case study: a multi-process system with the interaction between processes that deal with parts using common resources.