Abstract: Mo-MCM- 41 molecular sieve was prepared by hydrothermal synthesis method, and BO33-/ZrO2/Mo-MCM- 41 molecular sieve was prepared by impregnating Mo-MCM- 41 successively with H3BO3 and Zr(SO4)2 solutions. BO33-/ZrO2/Mo-MCM- 41 molecular sieve was characterized by XRD,N2/adsorption-desorption,FT-IR and NH3-TPD measurement. The results show that the molecular sieve obtained possesses the characteristics of mesopores, good long-range order and crystallinity, and that BO33- and ZrO2 are combined with the framework of the molecular sieve so that its acidity is improved. To find out a new method for synthesize polymerized rosin to replace the conventional methods using sulfuric acid as catalyst that exists serious disadvantages, the mesoporous molecular sieve was firstly used under supercritical CO2 condition. It was shown in the reaction that the supercritical CO2 fluid was favorable to the synthesis of polymerized rosin, and that BO33-/ZrO2/Mo-MCM- 41 molecular sieve exhibited good catalytic activity. Under supercritical carbon dioxide conditions,the product which showed a softening point of 106℃ was obtained by using BO33-/ZrO2/Mo-MCM- 41 mesoporous molecular sieves as catalyst. The reason for decrease of catalyst activity was studied by FT-IR measurement. It is the main factors leading to decrease of catalyst activity that acidity center of catalyst was lost after catalyst was used.