A transport model based on the mean free path consideration for high energy collisions has been developed. A transition from hadron state to a quark gluon plasma is included within the framework of the bag model. When the energy density in a collision is higher than a critical value, the bag breaks and partons are liberated. The partons expand and can recombine to form final state hadrons. The transport model could be used to simulate a whole process of high energy collisions which are/will be running at CERN and BNL. The evolution of the colliding system can be controlled and studied in detail. The model is used to discuss 1) an infinite meson system with or without the QGP being included. In pure meson gas case the Hagedorn limiting temperature is reproduced when the experimentally observed resonances are included. In the case with QGP being included, the results agree well with the Lattice QCD calculations; 2) proton-proton collisions. The experimentally observed pseudo-rapidity distribution and mulitiplicities of charged particles are reproduced at available energies and predicted for the experiments at very high energy. The probably GGP phase transition, turbulence, self-similarity and elliptic flow in very high energy of pp collisions are explored. A probably liquid-gas phase transition is discussed as well.