This paper researched the diurnal and seasonal changes of photosynthetic rate (Pn) of Jinguan,Molios and Strimoson apple ( Malus pumila Mill.).Results showed:the diurnal changes of Pn of Malus pumila cv.Jinguan and Strimoson apple trees species show similar patterns of one peak curves,and the peak values occured during 9:00 to 11:00 in a day.The diurnal changes of Pn of M.pumila cv.Molios show double peak curve,and the peak value occured during 9:00 to 11:00 also.On curves of seasonal changes o...