Formation method of semiconductor structure

A method for forming a semiconductor structure comprises the following steps: providing a substrate which comprises a substrate, a fin part located on the substrate, a first isolation structure located on the substrate exposed out of the fin part, and a gate structure which crosses the fin part and covers part of the top and part of the side wall of the fin part; a first mask layer is formed on the surface of the substrate, the substrate comprises a device region and an isolation region which are adjacent in the extending direction of the fin part, and the first mask layer exposes the top of the gate structure located in the NMOS region of the isolation region; removing the first mask layer and the gate structure located in the isolation region to form an initial isolation groove; taking the first mask layer as a mask, and removing the first isolation structure in the NMOS region of the isolation region; and removing the first mask layer and the fin part located in the isolation region to form an isolation gr