Effects of amino acid-N and ammonium-N on rice growth, N nutritional status and its mechanism were studied under sterilized aquiculture with ¹⁵N tracer technique in this paper. The results showed that the dry weights and N uptakes of the rice plants in the treatments of glycine-N (Gly-N) or mixture of glycine-N and ammonium sulfate-N (Gly-N+NH₄⁺-N) were significantly higher than that in the treatment of ammonium sulfate-N (NH₄⁺-N) after 51 days of sterilized aquiculture. The positive effect of Gly-N on the dry weight and N uptakes of rice plants was larger than that of NH₄⁺-N. The percentage of N in the rice plants derived from Gly-N in the mixture of Gly-N and NH₄⁺-N could reach a level as high as 55.66%. The activities of glutamateoxaloacetate transaminase (GOT),glutamate-pyruvate transaminase (GPT) and glutamate dehydrogenase (GDH) of the rice plants of indica and japonica cultivars in the treatment in Gly-N were all higher than in the treatment of NH₄⁺-N, respectively. Moreover, the activities of GOT and GPT in the roots and GDH in the leaves in the treatments of Gly-N were obviously higher than those in the treatments of NH₄⁺-N. The activities of GOT, GPT and GDH of the rice plants were positively promoted by its substrate glutamic acid (Glu).