The effect of P addition on the catalytic performance of La/HZSM-5 in methyl mercaptan abatement was investigated in the present work. It was shown that the addition of phosphorus could decrease the amounts of strong acid sites over the P-doped 13% La/HZSM-5 samples, but expected coke resistance ability was not obtained. To our surprise, P-doped 13% La/HZSM-5 samples exhibited decreased activity and stability for methyl mercaptan abatement. Moreover, the 13% La/HZSM-5 supported P catalysts were prepared and characterized by NH3-TPD, FT-IR, XRD and XPS, and it was found that the introduction of P species into La/HZSM-5 catalyst provokes a reaction with La2O3 and La(2)Ox(CO3)(y) species, which were reported to be active sites for methyl mercaptan conversion. As a result, P addition generated some inactive species such as AlPO4, Al(PO3)(3), LaPO4 and La(PO3)(3) species, causing the deactivation of the catalyst. These results conversely proved the necessary presence of active La2O3 and La2Ox(CO3)(y) species in the La/HZSM-5 catalyst for eliminating CH3SH.