a twist collapsible bag includes a collapsible bag body and a collapsible frame structure , which supports the collapsible bag body in shape , having a plurality of annular frame members horizontally arranged at different elevations and a plurality of vertical support rods vertically and equiangularly arranged between each two adjacent annular frame members and kept apart from the respective annular frame members at a predetermined gap such that when twisting the annular frame members relative to one another , the vertical support rods are biased from vertical to horizontal , thereby collapsing the twist collapsible bag into a flat condition .