Changji, a Miao nationality double-reed air-sounding instrument, consists of two juxtaposed pipes. "Changji" in Miao language means a pair of wind instruments. The Han people call it double-pipe. Can be played solo, ensemble or accompaniment.

When playing Changji, place the tube vertically, hold Changji with both hands, with the left hand on top, the ring finger and middle finger simultaneously press the fifth and sixth holes of the two tubes horizontally, the index finger press the seventh hole of the left tube, and the thumb press the back hole of the left tube; With the right hand down, the little finger, ring finger, middle finger, and index finger simultaneously press the first, second, third, and fourth holes of the two tubes. With two pipe whistles in his mouth.

Due to different specifications, the pitch is also uncertain. The common long product, the barrel tone is mostly c1, and its sounds are listed as: c1, d1, e1, f1, g1, a1, b1, c2, d2.

Changji has a high-pitched and bright pronunciation, and the timbre is pleasant to the ear. In addition to playing the same degree of double tones, it can also play simple two-voice harmony. For players with higher skills, he can play two-part tunes. It has richer expressive power than single-pipe wind instruments and has a strong mountain. Country style.