A rotatable coupling device applied to flexible display screen includes two folding sections, a hinge disposed between the two folding sections and at least one responsive structure, which is connected with the folding sections. When the folding sections are unfolded/folded around the hinge, the responsive structure is unfolded/folded along with the folding sections. The folding sections and the responsive structure are relatively displaceable so that during the unfolding/folding process, the transmission of the deformation amount on inner and outer faces caused by the bending of the hinge can be interrupted. Therefore, the deformation amount is prevented from being further transmitted from the responsive structure outward. When the flexible display screen is coupled with the responsive structure, the responsive structure is able to absorb the deformation amount so as to eliminate the pulling or compression effect on the flexible display screen due to the deformation amount.