Abstract: To investigate the prevalence of swine influenza virus（SIV）in large-scale pig herds in western of Fujian Province, China, a total of 457 healthy pig serum samples collected from Liancheng County, Shanghang County, Yongding District and Qingliu County between January 2022 to December 2024 were tested for swine influenza A antibodies by ELISA. Positive sera were further subtyped for H1, H3, H5, H7 and H9. Statistical analyses were performed according to different regions, years, seasons and growth stages. The results revealed that out of the 457 samples from large-scale pig farms in western of Fujian Province, 223 were positive for SIV antibodies, yielding an overall positive rate of 48.80%. Among the positive samples, H1 accounted for 77.58%（173/223） and H3 for 2.69%（6/223）, whereas H5, H7 and H9 were not detected. No significant differences in antibody positive rate were observed among regions or seasons（P＞0.05）, but the positive rate in 2023 was significantly higher than that in 2024 and 2022（P＜0.05）. Sow herds showed significantly higher prevalence than boars（P＜0.05）, and the positive rate of swine influenza A antibodies in sow herd and fattening pigs were significantly higher than that of snursery pigs and suckling piglets（P＜0.05）. These findings provide crucial data support for the formulation and implementation of regional SIV prevention and control strategies.