The adsorption recovery of HCFC-22 is an urgent task for environment protection. In this work we use the grand canonical Monte Carlo (GCMC) method to simulate the adsorption of HCFC-22 in terms of a slit-like activated carbon adsorbent. In our simulation the molecule of HCFC-22 is modeled by using the effective Stockmayer potential developed by this group. Heterogeneous activated sites with three different densities are imposed on the carbon walls. Three types of simulations are carried out: (1) The Gibbs ensemble MC method is used to test the Stockmayer potential parameters recommended here. (2) The Widom test particle method is used for determining the relationship of the chemical potential and the bulk phase pressure. (3) The GCMC method is used for adsorption simulations. Simulation results suggest that the optimum carbon slit pore is of width 1.75 nm and the activated site density is 0.8 sites/nm(2), when the adsorption is conducted at ambient temperature and pressure, and the exhaustion pressure is 0.011 MPa. In this case, the maximum amount of HCFC-22 would be recovered.