In this work, a series of novel indole 3-substituted-[1,2,4]triazole derivatives was designed and synthesized, and their structures were characterized by 1H, 13C NMR, high-resolution mass spectrometry, and single-crystal diffraction. Moreover, the antibacterial activities of the title compounds were evaluated against Xanthomonas oryzae pv. oryzae (Xoo), Pseudomonas syringae pv. actinidae (Psa), and Xanthomonas axonopodis pv. citri (Xac) by a turbidimetric method. Results showed that the title compounds had excellent bioactivity against Xoo, and their 50% effective concentration (EC50) ranged from 2.32 to 35.4 µg/mL, which were better than those of the positive control drugs Bismerthiazol (38.6 µg/mL) and Thiodiazole-copper (58.4 µg/mL). In particular, the EC50 values of compounds 53 and 9 against Xoo were 3.1 and 2.3 µg/mL, respectively.