The invention discloses an adjustable cover beam die. The adjustable cover beam die comprises a cover-beam bottom die, cover-beam lateral dies and cover-beam end dies; the cover-beam bottom die comprises a left-end bottom die body, a right-end bottom die body and a grouting sleeve positioning mechanism, and the left-end bottom die body, the right-end bottom die body and the grouting sleeve positioning mechanism are of width adjustable structures; the cover-beam lateral dies comprise lateral-die supporting frames and lateral-die panels, height adjusting mechanisms and fastening devices are arranged at the lower portions of the lateral-die supporting frames, and at least two lines of the height adjusting mechanisms are arranged on the inner sides and the outer sides of the lateral-die supporting frames; the cover-beam end dies are arranged on adjustable supporting mechanisms at the two ends of the cover-beam bottom die, and the actual using lengths of the cover-beam end dies on the cover-beam bottom die are adjusted through the adjustable supporting mechanisms. By means of the adjustable cover beam die, by adjusting the cover-beam lateral dies and the cover-beam bottom die, the requirements of the cover beam dies of different types can be met, and pouring of the cover beam dies of the different types is achieved.