In this article the change of the free amino acid content of the different variety wheat organs above the ground and the relationship with the grain protein along with the modulation of nitrogen nutri-tion were studied. The results showed that the free amino acid content of leaf, ear axis and husks all increased continuously after anthesis and reached the maximum value after anthesis 14 days,then began to declined. The free amino acid content of stem and sheath increased slowly after anthesis and reached th...