Uneven deformation and related weld-bead migration are the important problems that needs to be solved during tailor welded blanks (TWBs) forming. The forming of box with TWBs based on a series of linearly increasing and decreasing variable blank holding forces (VBHF) over the stroke were studied by means of dynamic explicit finite element method. The terminative value of the linear VBHF trajectory decreased with the initial value increasing. Consequently the relation curve between the initial and terminative values was obtained, which can be fitted by a second-order polynomial. The numerical simulation results demonstrate that the linearly increasing and linear decreasing VBHF have different effects on TWBs forming. The linearly increasing VBHF is beneficial to the thicker blank side drawn in more easily whilst the thinner blank side is stretched more, so that the weld-bead migration is reduced obviously. Compared with the constant BHF, the linearly decreasing VBHF allows more deformation for the thicker blank side, distributes the deformation uniformly and thereby improves TWBs formability.