| The sunflower (Kangdi 115 in Xinjiang) grown in different saline soils was studied about photosynthetic rate (Pn) and its affecting factors measured respectively with LI-6400 during squaring stage. The results indicated that the Pn of three treatments changed in a single-peaked curve, with its peaks of the salt contents at 0.29% and 0.39% appearing at 10∶00 and its peak of the salt content at (0.68%) at 12∶00. Pn decreased while salt content increase. The relation between photosynthetic rate and its affecting factors were analyzed through the correlation analysis and path analysis. The results indicated that under different salt stresses different factors reduced photosynthetic rate. PAR was not major affecting factor of Pn. Pn was controlled by the stomata factor in weak salt stress. Stomata, stomata and non-stomata factors were mutually controlled under middle salt stress. Under srtong salt stress, it was controlled by non-stomata factor, and stomata and non-stomata factors were mutually controlled. |