The object of this study was to elucidate the effect of excess and deficiency nitrogen (N) on citrus growth, development and amino acid content. Using trifoliate orange as materials, the change of chlorophyll, growth, IAA and amino acid content were analyzed. The results showed, compare with CK, chlorophyll content increased 29.3% and decreased 29.9% respectively after 120 d excess and deficiency N stress; under both excess and deficiency N stress, the treated plant fresh weight of leaves and stems were lowered and new shoot length was shorter than that of CK; due to the IAA content in stem tip was 9.9% higher than that of CK, the growth of new shoot was restricted significantly under excess N stress. Amino acids analysis indicated that leaves possessed most of the amino acids among all tissues. Aspartate which the content was 1.7 g/(100 g) (dry weight) was the richest amino acid in trifoliate orange, but the content of cysteine, tyrosine and methionine were little or under detected. The content of most amino acids in leaves and biennial stems decreased under excess N stress, but increased under deficiency N stress. Compare to CK, the content of most amino acids in annual stems increased 0.8%48.3% under excess N stress, but decreased 15.0%54.3% under deficiency N stress. Under excess and deficiency N stress, the content of most amino acids in fibrous roots decreased 6.2%30.2% compared to CK. However, the content of different amino acids in taproot and lateral roots did not showed congruous change trend under excess and deficiency N stress.