It was of great practical significance to repair the toxicity of salt stress environment to soybean seedlings and maintain the balance between agricultural production and ecological environment in the Yellow River valley of China. ‘Xudou 20’ was used as the experimental material, a large-scale planting variety in the old Yellow River basin. Endophytes 131 and 137 isolated from soybean root nodule were taken as the research objects, and the soybean plants were cultivated by pot culture in intelligent artificial incubator. Salt stress group, bacteria suspension group and control group were set up to study the effects of inoculation treatments on the activities of superoxide dismutase (SOD) and catalase (CAT) of soybean seedlings under different NaCl stress. The results showed that when inoculated with endophyte 131 bacterial suspension and cultured for 14 days, the SOD activity was the highest (14.89 U•g−1•FW) at the salt concentration 50 mmol•L-1. When inoculated with 131 bacterial suspension (2:1) and cultured for 28 days, the SOD activity reached the highest (0.94 ug-1FW) at the salt concentration of 50 mmol•L-1, and the CAT activity amounted to the highest (1910 U•g−1•min−1). The 16S rDNA sequencing and phylogenetic analysis showed that the most similar strain of strain 137 was Bacillus cereus, and the most similar strain of strain 131 was Enterobacter ludwigii. Therefore, the activities of SOD and CAT in soybean seedlings inoculated with endophytes 131 and 137 increased at different degrees under salt stress, which could effectively alleviate the damage of salt stress environment to plants, and thus improve the stress resistance of plants.