The separation of an equal amount of m- and p-cresol isomers on HZSM-5 pellets using compressed propane as the carrier and as the desorbent was studied. The pore-opening size of HZSM-5 pellets was modified by the chemical liquid deposition technique. The water content in the original pellets and the concentration of the deposition agent, SiCl4, in cyclohexane were observed to have effects-on the adsorption capacity and p-cresol selectivity. For the column separation using the modified HZSM-5 pellets, the effects of temperature, pressure, and flow rate on separation effectiveness were examined. For an injection of 0.2 mi of cresol isomers and 20 g of the modified pellets packed in a column, the most appropriate conditions were at a temperature of 373 K, a pressure of 3.45 MPa, and a flow rate of 2.0 mL/min. To shorten the separation time, propane with a pressure higher than 3.45 MPa was suggested to flow into. the column after m-cresol was completely removed from the column.