Abstract: In order to characterize the serum biochemical parameters of Mongolia Cattle and other breeds of cattle under grazing condition, eight serum biochemical parameters of Mongolia Cattle, Angus Cattle and Hereford Cattle were determined by Microplate reader. The results showed that compared to Angus Cattle and Hereford Cattle, Mongolia Cattle had significantly lower serum content of GC, TG and BUN （P〈0.05）; the serum content of GH in Mongolia Cattle was significantly lower than that of Hereford Cattle （P〈0.05）, and was lower than that of Angus Cattle （P〉0.05）; the serum content of BG in Mongolia Cattle was significantly higher than that of Angus Cattle （P〈0.05）, and was higher than that of Hereford Cattle （P〉0.05）. Compared to Angus Cattle and Hereford Cattle, Mongolia Cattle had higher serum content of ISU and lower serum content of T3 and T4, but no significant differences were observed （P〉0.05）.