The main shortcomings of Petri Nets are the lack of composability and the node explosion problem when modeling of complex systems. A new Petri net model named Process Net (PrN) is proposed which has the characteristics of Process Algebras. By means of four composition operators, complex Process Net can be constructed from existing simple ones. A structured operational semantic for Process Net is defined so that a process net can be analyzed by Process algebra or Petri nets methods. An application example to illustrate the application and analysis method of Process Net is described.