Taking the different genotypes of Chinese cabbage（Brassica campestris ssp. chinensis（L.）Makino）cultivars, hyper nitrate accumulator SYM and low nitrate accumulator HGQGC as materials, we investigated the accumulation of nitrate, nitrate reductase activity (NRA) and the expression levels of NRT1and NRT2 in plant tissue. The results showed that different NH4+/NO3- ratios produced significant influence on nitrate accumulation and this influence varied with genotypes. SYM possessed stronger ability than HGQGC to absorb, accumulate and utilize nitrate especially under higher NO3- proportion treatments, and the NRA of HGQGC was more sensitive than SYM to different NH4+/NO3- ratios. The expressions of NRT1 and NRT2 mainly located in root, and the expression levels of NRT1 was higher significantly than that of NRT2. The expression levels of NRT1 and NRT2 can partly explain the different nitrate accumulations between SYM and HGQGC under different NH4+/NO3- ratios; however, the mechanism of it needs more research.