Abstract:The relations between understory in Chinese fir plantation, forest stand and site are expounded systematically by anatyzing data inves tagated from 53 sample plots. The results show that the understory in Chinese fir plantation has a great indication, which can be used as one of bases for site classification and evaluation of Chinese fir plantions. However, this indication value is limited unless the understories grow and develop to a certain stage, and results from this indication investigation can not be exaggerated.