Long-necked lute, three-strings and fretless. It has a wooden fingerboard, and the body is made from snakeskin stretched over a rounded rectangular resonator. The northern sanxian is generally larger, at about 122 cm in length, while southern versions of the instrument are usually about 95 cm in length. In Standard Chinese, 'san xian' means 'three strings.'

The sanxian is played with a plectrum.