Ludi (pinyin: Ludi), also known as deer whistle, is a lip-vibrating air-sounding instrument made of birch by Oroqen, Ewenki, Daur and other ethnic groups.

The body of the deer flute was originally made of horns, and later it was made of wood, and now it is mostly made of birch into the shape of horns. Different appearance styles, there are right-angle, rectangle, horn and diamond and so on. The outer body of the deer flute is often hooped with three to five metal rings, and a belt is tied at both ends, which can be slung over the shoulder.

The deer flute is popular in the Oroqen Autonomous Banner of Hulunbuir League, the Ewenki Autonomous Banner, the Moridawa Daur Autonomous Banner, the Butha Banner, and Huma and Xunke in Heilongjiang Province.

The deer flute was originally a hunting instrument. The Oroqen, Ewenki, Daur and other ethnic groups made a living by hunting. For a long time, they have accumulated rich hunting experience and created a unique hunting instrument—the deer flute.