The study aimed to find non-toxic and pollution-free post-harvest prevention and treatment methods replacing chemical fungicides to enrich the resources of mango stalk rot antagonist bacteria. Botryodiplodia theobromae Pat. and Phomposis mangiferae Ahmad were used as the indicator fungi, and actinomycetes with antagonistic effects on stalk rot fungi were isolated and screened from the rhizosphere soil of mango trees by the plate dilution and dual culture method. The classification status, live prevention effects, and the antimicrobial mechanism were preliminary studied. Antagonists A2, B85 and D16 were selected, which had antimicrobial effects and good genetic stability against both Botryodiplodia theobromae Pat. and Phomposis mangiferae Ahmad, and had inhibitory effects on Colletotrichum gloeosporioides, Pestalotiopsis mangiferae, Alternaria alternate and Botrytis cinerea, with a wide antifungal spectrum. In the live test, on the 3^rd day after inoculation, there were no significant differences in the diameter of the fruit lesions treated with antagonist strains A2, B85 and D16 (8.58, 8.50, 7.83 mm) and the imimerine-treated group (6.33 mm), but significantly lower than that of the control group (20.58 mm). Strains A2 and B85 were identified as Streptomyces malaysiensis, and D16 was Streptomyces lydicus. Strains A2, B85 and D16 inhibited the occurrence of pedicle rot by producing active substances with antimicrobial effects, inhibiting spore germination of dipodol, nutritional competition, and improving the activity of fruit SOD, POD and CAT. Among the three antagonistic strains, the D16 could also produce volatile organic compounds with antimicrobial effects to inhibit the occurrence of pedicle rot fungi. The three strains had certain antagonistic effects on pedicle rot bacteria and could be further studied.