The effects of alkali metals (Na+,K+) on the exchange degree of Hβ zeolite under different conditions and the conversion of α(or β)-methylnaphthalene over the alkalized zeolites were studied. The results showed that the H+ of Hβ zeolite is totally replaced by the Na+ of NaCl solution, while partially exchanged by the K+ of KC1 solution, there is an exchange equilibrium between the H+ and K+ for Hβ zeolite (Si/Al=17.23) and the value of equilibrium is 88.39. The exchange degree also increases with increasing the Si/Al of the samples. It was suggested that these resluts are attributed to the electrostatic field in the pore of Hβ zeolite and the nature of zeolite and the properties of alkali metal. The isomerization of α(or β)-methylnaphthalene is the main reaction over the samples and it is more favour on the proper acid-base sites of KHβ zeolite. The effects of alkali metals (Na +, K +) on the exchange degree of Hβ zeolite under different conditions and the conversion of α (or β) -methylnaphthalene over the alkalized zeolites were studied. The results showed that the H + of Hβ zeolite is totally replaced by the Na + of NaCl solution, while partially exchanged by the K + of KC1 solution, there is an exchange equilibrium between the H + and K + for Hβ zeolite (Si / Al = 17.23) and the value of equilibrium is 88.39. The exchange degree also increases with increasing the Si / Al of the samples. It was suggested that these resluts are attributed to the electrostatic field in the pore of Hβ zeolite and the nature of zeolite and the properties of alkali metal. The isomerization of α (or β) -methylnaphthalene is the main reaction over the samples and it is more favorite on the proper acid-base sites of KHβ zeolite.