[Objective] This study aimed to provide scientific basis for the early selec-tion and breeding of excellent Catalpa bungei clones. [Method] The Li-6400 portable photosynthesis system was used to analyze the photosynthetic characteristics of five Catalpa bungei clones （1-3, 1-4, 004-1, 015-1 and 7080）. [Result] Al five Catalpa bungei clones had similar change trends of light response curves, but their maxi-mum net photosynthetic rates （Pmax） were in the order of 1-3＆gt;7080＆gt;015-1＆gt;004-1＆gt;1-4, showing that clone 1-3 and clone 7080 had strong light environmental adapt-ability with the light saturation points （LSP） of 1 147.97 μmol/m2＆#183;s and 1 196.31μmol/m2＆#183;s, respectively, while clone 1-4 had the narrowest range of adaptation to light. There were differences in the total photosynthetic amount per area among the five clones that clone 1-4 was the best of 433 974.24 μmol/m2, fol owed by clone 1-3 of 401 290.20 μmol/m2. The transpiration rates （Tr） and stomatal conductances （Cond） of the five clones presented the same change trend. And the diurnal varia-tion curves of net photosynthetic rate （Pn） of clone 1-3, 1-4 and 015-1 showed two typical peaks with obvious midday depression, while clone 004-1 and 7080 didn’t. [Concluson] Considering a variety of photosynthetic characteristics of indica-tors, photosynthetic capacity of clone 1-3 was the best among the five Catalpa bungei clones.
