Abstract: Al₃Ti particle reinforced Al matrix composite under different process conditions were prepared by using hot pressing device through in-situ reaction with 99.00wt% aluminum metal as substrate and titanium wire with 40 mesh as reaction source. The results show that, with the increase of the reaction temperature and time, the in-situ reaction becomes more adequate. The mechanism of in-situ reaction is that aluminum atoms migrate through the titanium boundary layer then diffuse to the product layer and react and form Al₃Ti. At the same time, the front of the solid-liquid interface keeps advancing,and the active titanium atoms are pushed into the aluminum solution, and Al₃Ti grains further grow. The optimum reaction conditions are as follows: reaction temperature of 850 ℃, heat preservation for 1 h and pressure of 12 MPa. Under these conditions, the microhardness of the composite is 10 times of that of the aluminum matrix, and the wear rate of the composite is 1/5 of that of the pure aluminum matrix. The strengthening mechanism of Al₃Ti/Al matrix composites prepared by in-situ reaction mainly includes particle strengthening, dislocation strengthening and dispersion strengthening.