A method for forming the semiconductor structure includes: providing a substrate, forming a sacrificial layer and an active layer on the sacrificial layer on the substrate; etching the active layer and the sacrificial layer to form active lines extending along a first direction; forming a first isolation layer that fills a spacing between the active lines; etching ends of the active lines to form openings, and exposing the sacrificial layer on side walls of the openings; removing the sacrificial layer along the openings, and forming gap between a bottom of the active lines and the substrate; and filling the gaps with a conductive material to form bit lines extending along the first direction.