The composite materials of continuous Al₂O_3f/ZL210A alloy with 40% of Nextel610-Al₂O₃ fiber were fabricated via vacuum-pressure infiltration process, while the fiber was preheated at temperatures of 500, 530, 560 and 600℃, respectively before pressure-infiltration. The effect of fiber preheating temperature on the microstructure and mechanical properties of the composites of continuous Al₂O_3f/ZL210A alloy was investigated. The results show that the density of composites increases with the increase of fiber preheating temperature; Among others, the composite of continuous Al₂O_3f/ZL210A made out of the fiber Al₂O_3f preheated at 600℃ presents the highest density of 99.2%; The tensile strength of Al₂O₃ fibers extracted from the prepared composites depends significantly on their preheating temperature, namely the higher preheating temperature may results in the lower tensile strength, as an example, the extracted Al₂O₃ fiber, which was subjected to pre-heat treatment at 600 C, presents a rough surface morphology with tensile strength of only 1150 MPa; The fiber preheating temperature has a significant effect on the tensile strength of continuous Al₂O_3f/Al composites. Indeed, the composites fabricated with Al₂O₃ fibers, which were preheated at 500, 530, 560 and 600℃ respectively, possess corresponding tensile strength of 298, 465, 498 and 452 MPa. The existed defects and damages on fibers, as well as the interfacial reaction between fibers and the matrix may be the main factors affecting the strength of the composites of continuous Al₂O_3f/ZL210A alloy.