H3PW12O40×nH2O (HPW) supported on hexagonal mesoporous silica (HMS) was prepared via impregnation method to obtain modified mesoporous HMS (HPW/HMS). The surface structure and acidty of the samples were characterised. The catalytic performance of HPW/HMS was tested through Friedel-Crafts acylations of 2-methoxynaphthalene (2-MN) with acetic anhydride (AA). The results showed that the obtained HPW/HMS catalyst displayed a typical mesoporous structure. HPW was well dispersed on the HMS support, and the acidity increased with the amount of HPW loading. Under the conditions of 120℃, 4 h, HPW/HMS 0.3 g, molar ratio of 2-MN to AA 1:2, the conversion rate of 2-MN was 75.3%(mol) and the selectivity of the main product 2-methoxy-1-acetonaphthone was up to 83.0%(mol). Repeated experiments demonstrated a slight decline in the catalytic activity.