A computational model for hybrid systems consisting of a non-trivial mixture of discreta cvents and continuous activities is presented. Based on this model, a spedcification language, Parallel Hybrid Machine (PHM), which allous us to specify a complex hybrid system in a paralled wag with a graphic representation, is formalized. As a case study, a graphic representation, is modeled by PHMs. Moreover,the PHMs and Hybrid Projection Temporal Logic (HPTL) share a common computational model. Thes enables us to model, analyze and verify a hybrid system in a uniform manner.