Abstract: The protective effect of Sm-Gly-VB₆ on the harm of soybean seedlings by acid rain was studied through vermiculite cultivation experiment．The results show that under acid rain(pH2．5)stress，the chlorophyll content and the chlorophyll a／b ratio reduce；the cell membrane permeability increases and the activity levels of catalase(CAT)decrease．However，under the same acid rain stress，in the soybean seedlings sprayed with 50 mg／kg Sm-Gly-VB₆，the harmfulness of chlorophyll content，the cell membrane permeability，and the catalase(CAT)activity are reduced．Therefore，Sm-Gly-VB₆ can reduce the harmful effect of acid rain on soybean seedlings.