The parent sheet selection in TWB designing is largely dependant on the effect of parent materials parameters on formability of TWBs. Experiments and FE simulations were performed to study the effect of material parameters of TWB’s parent sheets such as t (thickness ratio), k (strength factor of materials), n (strain hardening index), r (anisotropy index) on LDH and weld-line movement of TWB. Orthogonal experiments and range analysis were used to analyze the sensitivity on effect of different parameter on LDH and weld-line movement. The results show that LDH of TWB decreases with increasing ration of stronger sheets parameters to weaker ones, and the rate decreases gradually; in contrary, weld-line movement increases and the increasing rate decreases gradually. Furthermore, different parameters make various contributions to LDH and weld-line movement of TWBs and the effect degree of each parameter changes with different thickness ratios.