To improve the traditional erhu, the treble volume is weak, poor brightness, as well as the problem of unified sound, Hong Kong Chinese Orchestra to replace when the ensemble snakeskin polyester film, and spread throughout the violin class family. In this paper, by spectral analysis perspective view of environmental protection erhu, environmental Gaohu, environmental Zhonghu and environmental gehu in Hu et al., On the Timbre of data to put forward their views by this issue.