Abstract: The formability of tailor-welded blanks（TWB）was investigated by experiment, and the influence of thickness ratio and weld position on formability of TWB was mainly analyzed. Cupping and bulging experiments were carried out on DX53D+Z steel plates with three different thickness ratios of 0.6/1.2,1.0/1.2 and 1.2/1.2 mm. By adjusting the position between the punch and weld seam, the proportion of thin and thick sheet metal was obtained, and the cup value IE and the limiting dome height were measured. The failure positions of the material and the movement of the weld during the test were analyzed. The results show that the formability of TWB is worse than that of base materials. Thickness difference is an important factor affecting the formability, a greater difference in thickness results in a worse formability.With the increase of the amount of the weld shifting from the center of the punch, the IE value decreases first and then increases, and when the proportion of thick sheet metal is larger, the IE value is higher. In the bulging experiment, with the increase of thickness difference, the strain path of the material is transferred to the plane strain mode, which reduces the forming ability of the material.