A vertical double-diffused field-effect transistor comprises an N-type substrate, an N-type epitaxial region, a first P-type body region, a second P-type body region, two first N-type injection regions, two second N-type injection regions, a third N-type injection region, a first P-type injection region, a second P-type injection region, a grid oxide layer, a poly-silicon layer, a dielectric layer, a first through hole and a second through hole, wherein the first P-type body region and the second P-type body region are formed on a surface of the N-type epitaxial region, the two first N-type injection regions are arranged on a surface of the first P-type body region, the two second N-type injection regions are arranged on a surface of the second P-type body region, the third N-type injection region is arranged on a surface of the N-type epitaxial region, the first P-type injection region is arranged between the two first N-type injection regions, the second P-type injection region is arranged between the two second N-type injection regions, the grid oxide layer and the poly-silicon layer are sequentially formed on the N-type epitaxial region, the first P-type body region, the secondP-type body region, the first N-type injection region and the second N-type injection region, the dielectric layer is formed on the poly-silicon layer and on the first N-type injection region, the second N-type injection region and the third N-type injection region, the first through hole penetrates through the dielectric layer and is corresponding to the first N-type injection region and the first P-type injection region, and the second through hole penetrates through the dielectric layer and is corresponding to the second N-type injection region and the second P-type injection region.