Abstract: To explore the changes in leaf morphological characteristics and nutrient content of Pleioblastus amarus during its expansion into tea gardens, and reveal the adaptation strategies and nutrient acquisition characteristics, the study analyzed the response of leaf functional traits of 1-year-old and 2-year-old P. amarus during the expansion of P. amarus into tea garden. Four plots were established: P. amarus forest central area(BF), P. amarus forest interface area(BA), mixed forest interface area(MA), and mixed forest center area(TB). The findings revealed that along the direction of the expansion of P. amarus to the tea plantation, the leaf morphology of 1-year-old bamboo showed a trend of gradual increase, and the performance was the highest in the TB sample site, but the leaf morphology of 2-year-old bamboo showed a "V"-shaped change with the expansion of P. amarus to the tea plantation, and the performance of each index was the lowest in the BA sites; the values of the specific surface area of the leaf and the fluctuating asymmetricity of the leaf area of 1-year-old bamboo decreased significantly in the BA sites, but the differences of this index among the sample sites were not significant in 2-year-old bamboo. The CNP content of the 1-year-old bamboo leaf was significantly higher than that of other samples in the BA sites, while the CN content of the 2-year-old bamboo leaves showed the opposite behavior. The C∶N, C∶P, and N∶P of leaves of different ages of standing bamboo showed a "V" type change along the direction of the expansion of P. amarus to the tea plantation, and decreased significantly in the BA sites. The leaf width, leaf area, leaf thickness, leaf dry weight, and specific leaf area indexes of 1-year-old bamboo were gradually higher than those of 2-year-old bamboo with expansion, and the differences were obvious in the TB sites; the CNP content of 1-year-old bamboo was higher than that of 2-year-old bamboo among all the sampling plots, but the performance of C∶N, C∶P and N∶P was opposite, and all the indexes showed obvious age differences in the BA sites. Overall, the trade-off relationships among functional traits of P. amarus leaves were adaptively adjusted along the direction of expansion, with significant age effects in the bamboo-tea interface region where resource competition is intense.