In order to identify the immune effect of foot-and-mouth disease（FMD）in large-scale farms in Lingling District of Yongzhou City of Hunan Province，during the period of prevention in springs and autumns from 2020 to 2022，4 301 serum samples were collected from 337 farms/times in 13 townships under the district to detect antibodies against FMD by blocking ELISA，then the test results were analyzed based on the distribution of time，inter group and space. The results showed that the average immune qualification rate of FMD-O at farm level was 84.27% across the district，while the individual rate was 87.17%，increasing year by year. The immune qualification rates of cattle farms/households and individuals were the highest，which were 88.89% and 90.04%，respectively，followed by swine farms，85.64% and 89.10%，respectively，and lowest in sheep farms，77.78% and 79.75%，respectively，and the immune qualification rate of farms/households in sheep farms was statistically different from that in cattle farms（P＜0.05），that of individuals in sheep farms was also different from that in swine farms（P＜0.05）and cattle farms（P＜0.01）；the immune effect was better in Huangtianpu and Jielyuqiao Townships where the immune qualification rate exceeded 90%，but poorer in Shuikoushan and Dangdi Townships where the immune qualification rate was slightly higher than 70%，and the difference was statistically significant（P＜0.05）. In conclusion，the immune effect of FMD-O was good in general in large-scale farms in Lingling District，but different depending on regions and animal populations to some extent，which revealed that the guidance and training on immunization technology should be increased in farms，daily monitoring should be strengthened，and sheep population should be timely vaccinated and compensated，so as to maintain a high level of qualification rate of FMD across the district，and to prevent potential occurrence of an outbreak.