Shape-selective alkylation of polycyclic hydrocarbons has been the focus of many recent studies1-5 for preparation of symmetric intermediates such as 2,6-dialkylnaphthalene (2,6-DAN) which are used for synthesizing advanced polymer materials. Among 2,6-DANs, 2,6-dimethylnaphthalene (DMN) is regarded as the most suitable desirable intermediate with which can be oxidized with high selectivity reactivity in process of oxidation into 2,6-naphthalenedicarboxylic acid (2,6-NDCA), a monomor for aromatic polyester materials.Therefore, effective synthesis of 2,6-DMN has been become an important subjectstudied extensively.In this work, we compared the effects of potassium and phosphorus modification on the selectivity and activity of ZSM-5 for the methylation of 2-MN with methnol, and identified the promising direction for modification towards increasing the ratio of 2,6/2,7-DMN. Furthermore, we aimed to clarify the reason why the modified HZSM-5 zeolites exhibit higher selectivity for the methylation of 2-MN.Over KZSM-5(1.0), selectivity of DMN and 2,6-DMN were 72.8% and 54.1% respectively. Especially, at 6th hr of TOS, the selectivity to 2,6-DMN reached to 58%. The yield of 2,6-DMN was around 9.0% which is one of the best results as we know according to the literature.P and K modification showed totally opposite impact on ratio of 2,6/2,7-DMN for different effct on the acid properties of HZSM-5.