Abstract：Unstructured triangle grid is used as the basic grid cell. Based on the variable hard sphere (VHS) model, the Borgnakke-Larsen phenomenological model, the chemical reaction model of Bird and the Cercignani-Lampis-Lord(CLL) gas surface interaction model, the rarefied gas Direct Simulation Monte-Carlo (DSMC) codes in Fortran are developed, which can simulate the relaxation of internal energies, the thermodynamic non-equilibrium and the chemical reaction non-equilibrium. To take advantage of the parallel computation on multi-core computers, the parallel OpenMP model is incorporated into the DSMC method, and the unstructured DSMC parallel program can process numerical simulations on multi-core computers. The hypersonic airflow past cylinder is simulated in different cases of different rarefied regions to see the effect of thermal non-equilibrium. The numerical results have verified the rationality of the DSMC parallel program. For example, the computation efficiency after parallelization is nearly doubled using double-CPU or dual-core computers.