Abstract: In order to understand the infection of clinical mastitis-derived pathogens in dairy cows from some areas of Jiangsu Province, and its relationship with the regional and monthly distribution, in this experiment, six large-scale farms in Northern Jiangsu Province（Xinyi City, Sihong County, Huaian City）, Central Jiangsu Province（Yancheng City, Taizhou City） and Southern Jiangsu Province（Zhangjiagang City） were selected. From May to December 2021, 316 milk samples of clinical mastitis were collected for the isolation and culture of the pathogens, and PCR amplification and sequencing identification of 16S rDNA gene; the results of pathogen identification were based for the analysis on the detection of the pathogens in different areas and months in Jiangsu Province. The results showed that among 316 milk samples of clinical mastitis, 287 samples were detected with the pathogens, with a detection rate of 90.82%. There was significant difference in the detection of the samples between different areas; a total of 14 pathogens were detected in Northern Jiangsu Province, with a detection rate of 92.52%; a total of 10 pathogens were detected in Central Jiangsu Province, with the highest detection rate, reaching 97.01%; and only 9 pathogens were detected in Southern Jiangsu Province, with the lowest detection rate of 68.57%. The detection of the samples also varied between different months; in December, the detection rate of pathogens was the highest, reaching 100%, but the lowest number of pathogen types was only 8. The detection rates of pathogens in May, June and July was lower than those in other months, but there were many types of pathogens. There was the difference in the infection patterns of clinical mastitis pathogens in dairy cows between different areas; 7 pathogen infection patterns only appeared in Northern Jiangsu Province, and 6 or more pathogen infection patterns were not detected in Southern Jiangsu Province. Except for December, which was dominated by 4 and 5 pathogen infection patterns, 2 and 3 pathogen infection patterns were the most common in the remaining months. The dominant bacteria causing clinical mastitis varied by areas and months. The pathogens in Northern Jiangsu Province were mainly Klebsiella pneumoniae, the genus Staphylococcus, Escherichia coli and yeast; the genus Staphylococcus was the dominant pathogen in Southern Jiangsu Province. In October, the detection rates of Mycoplasma bovine and Staphylococcus aureus were the highest, reaching 72.41% and 51.72%, respectively; in December, the detection rate of the genus Staphylococcus was the highest, reaching 86.67%; in other months, the samples had the highest detection rates of Klebsiella pneumoniae.The results suggested that the overall detection rate of clinical mastitis-derived pathogens in dairy cows in six farms in Jiangsu Province was high, and there was difference in the detection rates of pathogens, the detection types of pathogens and the distribution of dominant pathogens in different areas and different months.