Abstract: Mesoporous MoO3-ZrO2 composite oxides were prepared by sol-gel method and were characterized by XRD, BET, SEM and IR to study the effect of calcination temperature on crystal phase structure, specific surface area, pore size and morphology. The FCC gasoline hydrodesulfurization activity of the sulfided composite oxides was evaluated. The results show that at the calcination temperature of 550 ℃, the worm structure is appeared on the surface of ZrO2; At 650 ℃, Zr(MoO4)2 characteristic peaks begin to produce and at 700 ℃, ZrO2 is transformed from tetragonal phase to the monoclinic phase. It is concluded that the appropriate increase of the calcination temperature is beneficial to increase the average pore size and get the proper specific surface area, but too high calcination temperature can make composite oxide sintering and fracture. The MoO3-ZrO2 composite oxide calcined at 650 ℃has the highest HDS rate of 70.3%.