To study the effects of oversized rate on the mechanical properties of asphalt concrete，the three levels orthogonal tests were conducted considering three factors including the particles content of 19mm ~ 26.5mm (oversized rate), the filler concentration, the amount of asphalt and three levels. The Marshall stability, flow value and splitting tensile strength of asphalt concrete were measured, and the projection pursuit regression (PPR) was used to study the influences of oversized rate, filler concentration, amount of asphalt on the mechanical properties of asphalt concrete core wall. The results showed that, with the increase of oversized rate, both Marshall stability and flow values decreased first and then increased, the splitting tensile strength first increased and then stabilized. With the increase of concentration of filler, Marshall flow value and splitting tensile strength first increased and then decreased, Marshall stability decreased gradually. With the increase of asphalt contents, the Marshall flow value increased gradually, Marshall stability and splitting tensile strength decreased gradually. The the mechanical properties of asphalt concrete core wall were the best when the oversized was 40%, the filler concentration was 2.0, and the use of bitumen was 6.8%.