Abstract: The aims are to understand the change rule of blood biochemical indexes of Holstein cows in the lactation and dry milk period, and guide the actual production. In this experiment, jugular venous blood of cow was collected with disposable syringe and preserved in 2 mL centrifuge tube, ear number of each cow and sampling date were marked and recorded. After that, blood routine and blood physiological and biochemical indexes in the whole blood with anticoagulant were detected by an automatic blood cell analyzer. The results showed that the number of white cells increased to some extent in the early lactation period (P>0.05). Hemoglobin content had no significant change in the lactation period (P>0.05). Total protein (TP) peaked in the peak lactation period. The number of alkaline phosphatase (ALKP) was the maximum in the early lactation period. Alanine aminotransferase (ALT) reduced in the peak lactation period. The content of blood glucose was significantly higher in the peak lactation period than that in other lactation period(P<0.05).