The microstructure and mechanical properties of Al-20Cu alloy prepared by solid-liquid mixed casting were investigated by OP and SEM.The results show that grain size of α-Al phase in the alloy can be refined obviously,which is controlled less than 100 μm and spheroidized,and coarse dendrite can be eliminated.The eutectic lamellar spacing of CuAl₂-Al（Cu） in the alloy is reduced.Compared with those of the alloy in conventional casting,the tensile strength and elongation of the alloy in liquid-solid mixed casting are increased from 112 MPa to 205 MPa,and from 0.5% to 3.5%,respectively.