Truncation process method of fin field effect transistor

The invention discloses a truncation process method of a fin type field effect transistor, which comprises the following steps of: 1, providing a semiconductor substrate on which a plurality of fin bodies and first spacer regions are formed, and forming a first material layer to completely fill the first spacer regions and extend to the upper parts of the surfaces of the fin bodies to form planarized surfaces; 2, forming a first pattern structure comprising a plurality of first strip-shaped structures and second spacer regions; 3, forming second side walls on the side surfaces of the first strip-shaped structures to cover the tops of the fin bodies on the two sides of the first strip-shaped structures; 4, removing the first strip-shaped structure to form a second pattern structure formed by a second side wall; step 5, etching the first material layer and the fin body by taking the second side wall as a mask to realize truncation of the fin body; and step 6, removing the second side wall and the remaining firs