Kuoshi Naiyi (pinyin: kuò shī nǎi yī), also known as double flute, is a double-reed gas-sounding instrument of Uyghur and Uzbek nationalities. It is popular in Hotan in southern Xinjiang and Shanshan in eastern Xinjiang.

The kuosi is made of reeds on the tube body, and is made of two balamans with the same length, thickness and pitch tied side by side. In order to keep the two double-reed reeds at the top of the tube body from being deformed, two bamboo or wood pieces are used to clamp and fasten the lower part of the reed reeds.

Kuo Shi Nai is full of artistic charm because of its high volume, rich timbre and artistic charm. Often used in Uyghur and Uzbek folk bands, it is an indispensable characteristic wind instrument for solo, ensemble or accompaniment.