In order to master the epidemic situation of ketosis in perinatal cows in Changji Prefecture and study the impact of the disease on the production performance of cows,1 898 blood samples of perinatal cows in Changji Prefecture were collected for blood ketone detection,the incidence of ketosis and subclinical ketosis were statistically analyzed,and the differences in milk production,milk quality and immunity indexes among healthy cows,subclinical ketosis cows and ketosis cows were compared. The results showed that the incidence of ketosis and subclinical ketosis in perinatal cows in Changji Prefecture were 10.06% and 33.09%,the ketosis cows and subclinical ketosis cows compared with healthy cows,the average daily milk output decreased by 14.39%（P<0.05）and 5.26%（P<0.05）,the milk fat rate decreased by 11.99%（P<0.05）and 6.0%（P<0.05）,the lactose rate decreased by 6.14%（P<0.05）and 2.18%（P>0.05）,the milk protein rate decreased by 11.88%（P<0.05 and 5.80%（P<0.05）,and the number of somatic cells increased by 26.72%（P<0.05）and 16.29%（P<0.05）,IgA content decreased by 23.81%（P<0.05）and 9.52%（P>0.05）,IgG content decreased by 15.71%（P<0.05）and 7.33%（P<0.05）,IgM content decreased by 14.58%（P<0.05）and 6.25%（P<0.05）. In conclusion,there are ketosis and subclinical ketosis in perinatal cows in Changji Prefecture which can reduce the milk yield,milk quality and immunity of cows.