In view of the low mechanical strength and easy breakage of calcined dolomite when it is used as a biomass pyrolysis catalyst, one preparation method of porous ceramic balls with dolomite and quartz sand as main aggregate was proposed. The porous ceramic balls with high mechanical strength were impregnated with Al2(SO4)3 solutions (0.3mol/L, 0.5mol/L and 1.0mol/L) at 25℃ for 6 h after firing. The load of Al2O3 on dolomite base porous ceramic balls was increased with the increase of Al2(SO4)3 solution concentration. In horizontal tube furnace, the dolomite base porous ceramic balls supported Al2O3 were used as catalyst to carry out fast pyrolysis experiment of corn straw powder. The results showed that the yield of the biooil was increased firstly and then decreased with the increase of relative mass content of dolomite, while the yield of biochar was decreased firstly and then increased when the proportion of dolomite to quartz sand was 30∶70, 40∶60, 45∶55 and 50∶50, respectively. The yield of biooil reached the highest production rate of 3685% and the yield of biochar reached the lowest production rate of 25.11% when the proportion of dolomite to quartz sand was 40∶60. With the increase of Al2(SO4)3 solution concentration, the yield of biooil was decreased and that of biochar was decreased firstly and then increased. Compared with the untreated Al2(SO4)3 solution, the yield of biooil was decreased by 10.69%, 15.33% and 21.55%, respectively. The relative content of alcohols in the biooil was increased slightly and that of ketones, acids, aldehydes was decreased gradually. However, compared with those without catalyst and Al2(SO4)3 solution, the yield of phenols was increased significantly, indicating that the presence of Al2O3 was beneficial to the production of phenols. The main components of noncondensable pyrolysis biogas were CO, CO2, CH4 and H2, among which CO2 had the high volume fraction, accounting for about 63%. The volume fraction of CO was about 32%. The volume fraction of CO2, CH4 and H2 was increased and that of CO was decreased when the porous ceramic balls loading dolomite were used as catalysts. The experimental results would provide a reference for obtaining high valueadded chemicals from agricultural biomass.