Abstract: Daily and seasonal dynamic change pattern of transpiration of Phyllostachys edulis ’Pachyloen’ was determined by Li-6400 portable photosynthesis system.The results showed the diurnal variation of transpiration rate(Tr) changed with season,bimodality in summer,and single peak curve in autumn,winter and spring.The annual variation of transpiration was single peak curve,peaks(3.78 mmol•m^-2•s^-1) occurred in June,the lowest was only 0.33 mmol•m^-2•s^-1 in January,and the annual mean of Tr was 1.30 mmol•m^-2•s^-1.Compared with the transpiration dynamic variation of P.edulis,not only the value of transpiration rates are similar,but the transpiration dynamic variations are similar except for the diurnal variation of transpiration in autumn,bimodality to P.edulis and single curve to P.edulis ’Pachyloen’,which reflects the difference response characteristics of the two bamboos to climate.The annual transpiration variation of the two bamboos was identical,it is single peak curve:high in summer,plummeting in autumn and winter,and going up in spring.