The influence of matrix alloying, treatiment methods for the alumina-silicate fibers, and different binders, on the tensile strength of aluminium matrix composites (AMCs)reinforced by alumina-silicate fibers has been investigated. It is shown that the tensile strength of the AMC with ZL109 aluminium alloy as a matrix is higher than those of AMCs with other aluminium alloy matrices. The tensile strengths of AMCs reinforced by Mullite alumina-silicate fibers is higher than those of AMCs reinforced by Al 2O 3 fibers and the tensile strength of the AMC with silicasol binder is higher than that of the AMC with alumina binder. This phenomenon is explained in detail in terms of AMC fracture mechanisms.