二胡是中国最传统的民族弓弦乐器，有两根弦，现代二胡以纯五度定弦，在胡琴之中属于中高音域乐器。各地方根据需要和条件，独立发展出不同形制的弓弦乐器，如高胡，京胡，板胡，中胡等。唐朝时称西方、北方各民族为胡人，胡琴为西方、北方民族传入乐器的通称。至明清时期，胡琴成为弓弦乐器的通称。

五四运动时期，刘天华融合欧洲的音乐理论、演奏技巧，根据中国民间音乐特性及借鉴小提琴，将二胡定弦为d、a，并对二胡的演奏技巧进行革新，扩展二胡的表現力，并且为二胡创作《月夜》，《烛影摇红》多首独奏曲。著名二胡民间艺人华彦钧（阿炳）创作的《二泉映月》；作曲家黄海怀创作的二胡独奏曲《赛马》经常奏响在国际舞台。现代二胡作品出现，有《豫北叙事曲》、《三门峡畅想曲》、二胡協奏曲《长城随想》等。1980年到2000年以后，已出版的二胡独奏曲达数百首，并开始发展叙事曲，协奏曲，狂想曲等大型二胡曲。

1950年至1960年间，上海民族乐团、中央民族乐团等模仿交响乐团的职业民族乐团出现，增加对二胡专业的需求,随着狂想曲及大量西洋移植现代作品的出现,把二胡艺术推向了顶峰.

Erhu is a kind of violin (fiddle) with two strings which, together with zhonghu, gaohu, jinhu, etc, belongs to the "huqin" family. It is said that its origin would be dated up to the Tang dynasty (618-907). The erhu then developed in a different "schools". Two famous artists A Bing (1893-1950) and Liu Tianhua (1895-1932) made an exceptional contribution to the improvement of the erhu, and it was indeed due to the latter that the erhu, an instrument mainly for accompaniment in an opera, becomes a solo instrument. After 1949,the playing techniques, the repertoire have grown rapidly in the genres of solo, with ensemble as well as concerti with symphony orchestra. Erhu now has become one of the most popular instruments in China. In fact, the erhu plays the same role as the violin in the Western orchestras.

The erhu sounds similar to human voice, and can imitate many natural sounds such as birds and horse. It is a very expressive instrument, most well-known for playing melancholic tune, but also capable of play merry melody.