The air organization research is the basis of thermal environment control in air-conditioned compartment. Reasonable air organization can availably improve the passengers' thermal comfort. By k-ε turbulence model, the air fluid flow and heat transfer in air-conditioned hard-sleeper compartment are simulated numerically. The airflow field and temperature field are investigated in different air supply modes and air supply parameters. The comparison is carried out between the computed and the measured results of temperature and velocity fields. The agreement between them is quite well. A basis is given for the optimized design of air organization in the air-conditioned passenger compartment.