A metallic matrix shaping method is provided. A flatness of a plurality of points of the metallic matrix is measured by a shape test device, and a flatness margin of error H between a reference level and the flatness of the metallic matrix is calibrated using the least square method. A controller determines whether the points of the metallic matrix need to be shaped by comparing the flatness margin of error H and a permissive error range K. The controller calibrates a descending distance P by a mathematical formula of P=M+[(H−K)/D]/N+L. A shaping device shapes the metallic matrix according to the descending distance P and a shaping time. The above steps are repeated until the flatness of the metal is within the permissive error range K.