By analyzing the effects of nitrogen application level on the activities of key enzymes of nitrogen metabolism,nitrogen absorption and nutritional quality of kidney beans,the relationship between the activities of key enzymes of nitrogen metabolism and nitrogen absorption and nutritional quality was discussed,so as to provide the basis for saving fertilizer and improving quality of kidney beans. Kidney bean cultivar of ’Yingguohong’ was selected as of the material in a pot experiment. Four nitrogen application levels,N1（25 kg/ha）,N2（30 kg/ha）,N3（35 kg/ha） and N4（40 kg/ha） were set,and N0 was taken as control. The regular pattern ofNR activity,glutaminesynthetase（GS）,plant nitrogen content and grain nutritional quality of kidney bean at seeding stage,initial flowering stage,pod setting stage and grain filling stage were analyzed.The results showed that :（1）At the same growth stage,with the increase of nitrogen application rate,the NR and GS activities of leaves first increased and then decreased,and the NR and GS activities of N2 treatment were the highest. NR activity increased by 24.68% at initial flowering stage and GS activity increased by 18.21% at pod setting stage,compared with N0 treatment.（2） In the range of 0～30 kg/ha,nitrogen content,crude protein content and total starch content of kidney bean increased with the increase of nitrogen application rate. When the nitrogen application rate was 30～40 kg/ha,the nitrogen content and nutritional quality of each organ decreased with the increase of nitrogen application rate. The crude protein content and total starch content of N2 treatment increased by 12.38% and 9.34%,compared with N0 treatment.（3） The activities of NR and GS in leaves were positively correlated with the protein content and total starch content of kidney bean. Therefore,30 kg/ha of kidney bean in semi-arid area of Heilongjiang Province was the best nitrogen fertilizer application rate.