[Objective] Eperythrozoonosis is a zoonotic infectious disease caused by Eperythrozoon parasitic on the surface of red blood cells,plasma and bone marrow of humans and animals. [Method] To investigate the prevalence of eperythrosis in dairy cows in Runan County,748 dairy cows were selected from March 2020 to February 2021 for epidemiological investigation by field investigation, interrogation and laboratory diagnosis. [Result] The infection rate of eperyzosome disease in dairy cows in Runan County was 10.03%,among which the positive rate was the highest in lactating cows （13.02%）,followed by young cows （10.71%）,and the lowest in calves （5.91%）.July and August were the peak months of eperyzosome disease,with the incidence rates of 14.55% and 14.28%,respectively,and January had the lowest incidence rate of 6.67%. [Conclusion] The investigation provided scientific reference for the prevention and treatment of eperythrosomal disease in dairy cows in Runan County.