An aluminum borate whisker (Al18B4O33w) was recognized as an attractive reinforcement for the aluminum alloy, It is good strength, high wear resistance, good thermal stability and low cost, comparable with those of other whiskers such as SiC and Al2O3. In general, aluminum borate whisker reinforced AC4CH alloy composites have been produced by squeeze casting process, which is capable of promoting the higher specific mechanical properties. α+Al18B4O33w/AC4CH (α: SiO2, Al2O3, TiO2sol) composites were fabricated by squeezecasting method in which the molten aluminum infiltrated into the whisker preform. The primary objective of this study was to establish the influence of the fracture toughness of α+Al18B4O33w reinforced composite by different containing inorganic binder. In addition, the fracture mechanism was evaluated through the scanning electron micrographs. As results, fracture toughness the composite containing TiO2 sol was shows plane about 9.28Mpa-m0.5. TiO2 inorganic binder can enhance fracture toughness of the Al18B4O33w reinforced composite. In order to obtain Al18B4O33w reinforced aluminum composites to have good fracture toughness use of TiO2 inorganic binder is recommend.