Abstract:Study on additive-dominant genetic model and gene effects were conducted on the date of 6 Paki-choi (Brassica campestris L. ssp. Chinensis (L.) Makino)population including high nitrate concentration cultivar "Jiangsu Aijiaohuang"(P1), low nitrate concentration cultivar "Shanghaiqing"(P2), F1 population(P1×P2), F2 population(F1×F1) and B1 population(F1×P1), B2 population(F1×P2)。The result of joint scaling test showed that the population means for the nitrate concentration was 3028mg/kg, The additive effects of the genes on the nitrate concentration in "Jiangsu Aijiaohuang" was 2207mg/kg, more than the corresponding allele in "Shanghaiqing". The gene on the nitrate concentration in "Jiangsu Aijiaohuang" was dominant to the corresponding allele in "Shanghaiqing" with the degree of dominance of 0.45. The results of test of fitness indicated that additive-dominant genetic model was adequate for nitrate concentration in pak-choi. The result also showed that the heritability of nitrate concentration in pak-choi was 21.6%-56.1%.