Changji (pinyin: cháng jī), also known as double-pipe, Miao double-reed air-sounding musical instrument, is popular in Guangxi Zhuang Autonomous Region, Guixi Longlin Autonomous County, Bianya and other Miao inhabited areas.

Changji is made of two bamboo pipes of the same size and length tied side by side, divided into left pipe and right pipe, which are called male and female pipes in the folk, with a total length of about 30 cm. Each tube is equipped with a core and a whistle, and has a common gas card.

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 chords. Players with higher skills can also play two-part tunes, which are more expressive than single-pipe wind instruments and have a strong mountain range. Country style. Often used for solos, instrumental ensembles, or to accompany folk songs.

The more representative pieces are "Answered Tune", "Wen Pai Tiao", "Thanks Tune" and "Happy Tune".