This paper studied the second metabolism changes under the natural forest condition. Concentrations of total phenolics were measured in Fargesia denudate by a colorimetric method. The results showed that phenolic compounds in bamboo were present throughout the collected organs with the highest concentration in old leaves (2.05%) and the lowest content (0.20%) in shoots. Sunshine and air temperature influence the concentrations of total phenolics. With the increment in altitude and solar radiation, there is an obvious increase of total phenolics in young bamboo organs. By a data analysis, it has revealed that close relationship existed among the variation of total phenolics in different organs of Fargesia denudate, the environmental factors and the ingestive volume of the Giant panda (Ailuropoda melanoleuca).