A novel type of porous oil-absorbent microspheres based on poly(stearyl methacrylate-co-butyl acrylate) was prepared via suspension polymerization. By investigating the effects of the cross-linking agent, monomer ratio, initiator, stabilizer, water/oil ratio, and porogen agent on the oil absorbency of the prepared oil-absorbents, an optimized oil-absorbent microsphere OAM-T was obtained, and characterized by FT-IR and SEM. The oil absorbencies of OAM-T toward chloroform, toluene, gasoline, and diesel were measured to be 61.9, 32.6, 28.8, and 28.2 g/g respectively, with oil absorption saturation time being 1.0, 1.5, 2.0, and 3.0 hr. The oil retention of OAM-T toward the four oils is all above 95%. Besides in pure oils, OAM-T also has high oil absorbencies in oil-water mixture. It can be reused at least 12 times with little change in oil absorbency. Owing to its excellent oil absorption performance, OAM-T might find applications for removing oil spills and organic pollutants from water.