The invention provides a method for forming a contact plug, comprising: forming a gate, a sidewall spacer, a sacrificial sidewall spacer, a source region and a drain region on a substrate, wherein the sidewall spacer is formed around the gate, the sacrificial sidewall spacer is formed over the sidewall spacer, and the source region and the drain region are formed within the substrate and on respective sides of the gate; forming an interlayer dielectric layer, with the gate, the sidewall spacer and the sacrificial sidewall spacer being exposed; removing the sacrificial sidewall spacer to form a contact space, the sacrificial sidewall spacer material being different from that of the gate, the sidewall spacer and the interlayer dielectric layer; forming a conducting layer to fill the contact space; and cutting off the conducting layer, to form at least two conductors connected to the source region and the drain region respectively.