We propose a phenomenological model for the strong reaction. In the model we assume that the resonance states can be treated as elementary particles as the pion and nucleon and the physical processes can be described by the sum of the lowest order matrix elements. As an application of the model we study the proton-proton scattering below∼300 Mev. It is shown that the present model can successfully explain the experimental (YLAM) phase shifts if the pion, scalar boson and vector boson dominantly contribute to the nuclear force at this energy region.