The two-step nano-scale self-assembly technique and the framework structure mechanism for forming mesoporous supports were employed for preparing Al2O3-TiO2 complex supports with large pore volume that were applied for manufacturing the resid hydrotreating catalysts. The influence of different TiO2 contents and calcination temperatures on specific surface area, pore volume and pore size distribution of complex supports was studied. TEM and SEM were employed to characterize the Al2O3-TiO2 complex supports. Test results revealed that the specific surface area of Al2O3-TiO2 complex supports was the largest at a TiO2 mass fraction of 20%, and when the calcination temperature was in the range between 300℃ to 700℃, the pore distribution of the complex support was stable. Characterization of the complex support by TEM and SEM demonstrated that TiO2 was homogeneously distributed in the complex support, which was in favor of carrying active components. The Al2O3-TiO2 complex supports can function as the best catalyst support for resid hydrotreating catalysts.