The present invention provides a method for manufacturing a semiconductor structure, comprising the steps of: providing a semiconductor substrate, forming an insulating layer on the semiconductor substrate, and forming a semiconductor base layer on the insulating layer; forming a sacrificial layer and a spacer surrounding the sacrificial layer on the semiconductor base layer, and etching the semiconductor base layer by taking the spacer as a mask to form a semiconductor body; forming a dielectric film on sidewalls of the semiconductor body; removing the sacrificial layer and the semiconductor body located under the sacrificial layer to form a first semiconductor fin and a second semiconductor fin; and forming a retrograde doped well structure on the inner walls of the first semiconductor fin and the second semiconductor fin, wherein the inner walls thereof are opposite to each other. Correspondingly, the present invention further provides a semiconductor structure. In the present invention, a retrograde doped well structure is formed on the sidewalls of the two semiconductor fins that are opposite to each other, so that the width of the source/drain depletion layer may be effectively reduced, and thereby the short channel effect is reduced.