This research examined the identification method and genetic traits of low nitrogen resistant soybean at the seedling stage. 260 soybean varieties were used and subjected for pot experiments under normal and low nitrogen treatments， followed by examination of nine traits （such as SPAD， plant high， and shoot fresh weight） at the stage of the fourth compound leaf unfolding. By analyzing the phenotypic difference of soybean varieties under low nitrogen stress condition， as well as the low nitrogen tolerance coefficient， correlation analysis， principal component analysis， affiliation function， and regression analysis， the soybean varieties showing low nitrogen tolerance were identified. The significant differences at all the traits were observed under two different nitrogen-supplying levels， showing levels of variation among the traits and the varieties. The indexes of nine traits were refined using three indexes by principal component analysis. Based the value of the affiliation function and the comprehensive evaluation of low nitrogen tolerance in conjugation with cluster analysis， five categories （strong resistant， resistant， middle resistant， sensitive and most sensitive） were suggested. Seventeen soybean varieties were strong resistant categories， while seven were most sensitive categories. Through stepwise regression analysis， total dry weight， root dry weight， shoot fresh weight， SPAD of the second compound leaf， and SPAD of the first compound leaf， might be deployed as the principal indicators for evaluating low nitrogen tolerance in soybean.