Polie is a double-reed gas-sounding instrument of the Zhuang nationality. The Zhuang language is also called Bilie and Bielie. In Zhuang language, "wave", "bi" and "bie" all mean blowing, and "column" means pipe, which means blowing pipe. The Han people call it the Zhuang Suona. It is a folk musical instrument with a long history. After reform, it has become an excellent solo instrument with beautiful timbre and expanded range. Popular in Longzhou, Ningming, Pingxiang and Nanning in Guangxi Zhuang Autonomous Region.

The traditional wave train consists of a pipe body, a pipe whistle, a core and a bell mouth, with a total height of 32 cm to 40 cm.

The tube body is made of wood, mostly made of mulberry, pear or lychee wood produced locally. The upper part is thin and the lower part is thick, and the two ends are transparent. It is a hollow cone. The height of the tube is 20 cm to 26 cm. cm, the outer diameter of the tail end is 2.4 cm, and the inner diameter is 1.4 cm. There are seven circular sound holes on the front of the tube body, the diameter of which is 0.4 cm. The first hole to the end of the tube is 2.5 cm, and the first hole to the seventh hole is 16.2 cm. The distance between the holes is 2.7 cm, the appearance of the tube body is straight and smooth, and the ends of the tube are covered with tin hoops, which are engraved with patterns or patterns.

The whistle is usually made from silkworm cocoons or natural tree worm cocoons. It is 1.6 cm to 2 cm long and is a soft double-reed whistle.

The core, also known as the tube head, is a tubular body made of tin. The upper part is thin and the lower part is thick, and the length is 4 cm to 5 cm. A circle of protruding outer walls is cast on the periphery of the tin tube 1 cm away from the upper mouth, which is used as an air card when playing. The bell mouth is also known as the bowl. The bowl is made of wood and is made of the same wood as the pipe body. The shape is similar to the bell mouth of the Western musical instrument oboe, and it is relatively small. cm, the upper mouth of the bowl is smaller than the outer diameter of the tube tail, it is installed at the lower end of the tube body, and can be loaded and unloaded at any time.