Abstract: The relationship between the varietal adaptability to heavy manuring and net Photosynthetic rate was studied and three wheat cultivars with different adaptability to heavy manuring were used in the experiment. Results indicated that the order of net photosynthetic rate of the flag leaf Was: Taishan No.1 (adaptability moderate) >Jinan No.13 (strong) >Changle No.5 (weak) .Although the absolute value of the net photosynthetic rate changed with various environmental conditions in different years, the differences among various Cultivars were relatively Stable. The net photosynthetic rate of the flag leaf of Changle No.5 decreased significantly, while those of Taishan No.1 and Jinan No.13 were enhanced greatly with increasing nitrogen supply. The decrease of the photosynthetic rate after anthesis could be enhauced by increasing nitrogen supply.