Abstract: To investigate the effects of the fermentation broth of mixed bacteria FH-1 and NJ-1 in mitigating the combined stress of lead(Pb²⁺) and atrazine on the growth and development of soybean seeds and seedlings. The effects of mixed bacteria FH-1 and NJ-1 on the degradation of atrazine at different concentrations of Pb²⁺ were determined by liquid chromatography. The experimental results indicate that, after adding 0.02, 0.04, 0.06, 0.08, 0.1 and 0.2 mol·L^-1 Pb²⁺. At the first day, the low concentration of 0.02 mol·L^-1Pb²⁺ promoted the degradation rate of atrazine, and with the increase of Pb²⁺ concentration, the degradation rate of atrazine was inhibited. At the third and fifth days of culture, the degradation rate of atrazine was inhibited by adding Pb²⁺ atrazine at different concentrations. The results of seed germination test and seedling pot test showed that the combined stress of Pb²⁺ and atrazine significantly inhibited soybean seed germination, seedling growth and root development（P＜0.05）, and was higher than that of single stress; while the germination length and germination rate of soybean seeds increased by 46.76% and 36.36%, respectively, after the addition of mixed bacterial fermentation broth. Meanwhile, the relative stem and leaf dry weight and root length of seedlings were restored by 38.60% and 60.20%, respectively. In addition, root irrigation with the mixed bacterial fermentation solution increased the SOD and POD activities of seedlings roots under complex stress by 38.21% and 6.17%, respectively, and reduced the MDA content by 59.27%. And the reduced root vigor and bacterial population in the soil affected by the combined stress recovered 37.63% and 37.55%, respectively, after the addition of the mixed bacterial fermentation broth. Therefore, the fermentation broth of FH-1 and NJ-1 mixed bacteria can improve the antioxidant enzyme activity and root vigor to mitigate the damage of Pb²⁺ and atrazine combined stress on soybean seedlings, and then promote seedling growth.