Abstract: To investigate the clinical characters of cows’infertility and prevent and cure infertility effectively, the blood physiological and biochemical indexes of cows with infertility, uterus hyperplasia, endometritis or ovarian cyst were measured. Conventional blood indexes and biochemical indexes of diseased cows and healthy cows were tested by automatic blood cell analyzer and Vet Test biochemical analyzer. Results showed that endometritis caused a significant increase of white blood cells (P <0.05); but red blood cell count, hemoglobin content and lymphocytes percentage, monocytes percentage and neutrophils percentage had no significant change in the four cases. Ovarian cyst caused a significant increase of total protein (TP) in blood (P <0.05). There was no significant change in regard to alanine aminotransferase (ALT), alkaline phosphatase (ALKP) and blood glucose (GLU) in all cases (P >0.05); infertility, endometritis, and ovarian cyst could significantly reduce the concentration of calcium(Ca) in blood (P <0.05); besides, infertility, endometritis, and ovarian cyst could significantly increase the concentration of phosphorus ions (PHOS) in blood and break the balance of calcium and phosphorus (P <0.05); meanwhile, it was found in all groups that blood glucose concentration was lower than normal standard value. Thus, it indicated that the balance of calcium and phosphorus in blood can predict the infertility of cows as an auxiliary index. Additionally, keeping the balance of calcium and phosphorus in blood is one of the effective means to prevent and cure the infertility of cows in the early diagnosis of disease.