The invention discloses a preparation method of supported spherical aluminum oxide granules, which includes the following steps: 1) mixing pseudo-boehmite and metal oxide according to proportion uniformly to obtain a mixture powder, and mixing the mixture powder with an ammonium alginate water solution uniformly to prepare first composite spherical wet granules being 2-6 mm in granular size; and 2) soaking the first composite spherical wet granules in an acetic acid solution, and allowing the first composite spherical wet granules to stand for 4-12 h with relative humidity being 60-90% and temperature being 60-90 DEG C, drying the granules to constant weight at 60-90 DEG C, and calcining the granules at 500-650 DEG C for 4-12 h to prepare the supported spherical aluminum oxide granules. Components supported on the supporting spherical aluminum oxide are not liable to loss. The supporting spherical aluminum oxide granules various metal oxides are easily supported on the spherical aluminum oxide granules, wherein supporting and moulding can be completed just by one calcination process, and the granules are simple in preparation process and low in energy consumption.