In this study, a pot experiment was conducted to investigate the effects of different application rates of trichloroisocyanuric acid (TCCA) used as disinfectant on soil microbial community composition under potato continuous cropping obstacle. Four treatments of TCCA application rates were designed, including 0 (CK), 30 kg/hm² (S₃₀), 60 kg/hm² (S₆₀) and 120 kg/hm² (S₁₂₀). Compared to CK, S₆₀ and S₁₂₀ significantly increase soil pH by 0.15 and 0.26 units (P<0.05), increase soil dissolved organic carbon (DOC) content by 30.4% and 83.5% (P<0.05), increase soil NH₄⁺-N content by 3.3 and 9.7 times (P<0.05), respectively. S₆₀ and S₁₂₀ significantly shift the relative abundance of dominant microorganism at phylum and genus levels (P<0.05). Compared to CK, S₆₀ and S₁₂₀ increase the relative abundances of Proteobacteria and Ascomycota by 55.3% and 85.9%, 16.7% and 35.1% at the phylum level, respectively; while decrease the relative abundance of potato pathogen Streptomyces by 35.7% and 57.1% (P<0.05) at the genus level, respectively. Principal coordinate analysis (PCoA) shows that S₆₀ and S₁₂₀ significantly change the community structures of bacteria and fungi compared to CK. In addition to the direct effects of TCCA, redundancy analysis (RDA) suggests that soil pH and NH₄⁺-N content are also the key factors affecting microbial community composition.