Abstract:The seasonal photosynthetic response of Phyllostachys edulis ‘Pachyloen‘ to light intensity, CO2 concentration, temperature and humidity were measured with Li-6400P. The main study results were as follows:The seasonal photosynthetic variation tendency of Ph. edulis ‘Pachyloen‘ to light intensity was summer>autumn>winter>spring for Pmax, spring>autumn>winter>summer for LCP, autumn>summer>winter>spring for LSP, and summer> autumn>winter>spring for AQY. The seasonal photosynthetic variation tendency of Ph. edulis ‘Pachyloen‘ to CO2 concentration was spring>autumn>summer> winter for LCP and CCP, and summer>autumn> winter>spring for CE. The optimal temperature for photosynthesis of Ph. edulis ‘Pachyloen‘ ranged from 20 to 30 ℃, equivalent in spring and autumn, higher in summer and lowest in winter. The optimal humidity for photosynthesis of Ph. edulis ‘Pachyloen‘ ranged from 40% to 65%, its seasonal variation tendency was autumn>summer>winter>spring. As a cultivar of Ph. edulis, the characteristics of photosynthetic responses of Ph. edulis ‘Pachyloen‘ to environmental factors were similar with Ph. edulis. It indicated their close phylogenetic relationships.