A method for forming a semiconductor device is disclosed. A method for forming a semiconductor device includes forming a first bit line contact over a semiconductor substrate, forming a second bit line contact that is coupled to the first bit line contact and has a larger width than the first bit line contact, and forming a bit line over the second bit line contact. When using the semiconductor device having a buried gate, although the bit line is formed to have a small width and the bit line pattern is misaligned, the method prevents incorrect coupling between a bit line and a bit line contact, so that it basically deteriorates unique characteristics of the semiconductor device.