A multi-fin field effect transistor includes a substrate, an oxide layer, a conductive layer, a gate oxide layer, and a doped region is provided. The substrate is surrounded by a trench, and there are at least two fin-type silicon layers formed in the substrate in a region prepared to form a gate thereon. The oxide layer is disposed in the trench and the top surface of the oxide layer is lower than that of the fin-type silicon layers. The conductive layer is disposed in the region prepared to form a gate. The top surface of the conductive layer is higher than that of the fin-type silicon layers. The gate oxide layer is disposed between the conductive layer and the fin-type silicon layers and disposed between the conductive layer and the substrate. The doped region is disposed in the substrate on both sides of the conductive layer.