The purpose of this experiment was to compare the relationships of mammary oxygen metabolic traits, body health and mammary oxidative stress of Holstein dairy cows in different lactating periods. Eighteen early-lactating cows[days in milk:(61.80±3.72) d; milk yield:(55.65±3.95) kg/d; (2.74±0.19) parities; body weight:(701±55) kg] and 16 late-lactating cows[days in milk:(289.10±6.78) d; milk yield:(12.27±4.70) kg/d; (2.81±0.15) parities; body weight:(727±63) kg] were selected in the current study. The blood samples of mammary vein and caudal artery of these 34 cows were collected in the same time to measure the blood gas parameters, blood routine indexes and oxidative stress indexes, and the oxygen metabolism related indexes such as mammary oxygen supply were calculated combined with the above results. The results showed as follows:in terms of mammary oxygen metabolism, compared with those of late-lactating dairy cows, the mammary total oxygen consumption (P=0.01) of early-lactating dairy cows was extremely significantly increased, the oxygen content in coccygeal artery (P<0.01) was extremely significantly decreased, the oxygen consumption of producing a unit of milk (P=0.02) was significantly decreased, and the oxygen content in mammary vein (P=0.06) tended to decline. In terms of mammary gland oxidation stress and antioxidant stress, the contents of reactive oxygen species (P=0.09), malonaldehyde (P=0.07) and oxygen radical antioxidant capacity (P=0.07) in mammary vein plasma of early-lactating dairy cows were higher than those of late-lactating dairy cows; the malonaldehyde content (P=0.01) in milk of early-lactating dairy cows was extremely significantly higher than that of late-lactating dairy cows, and the oxygen radical antioxidant capacity (P=0.07), glutathione peroxidase (P=0.06) and superoxide dismutase activities (P=0.07) in milk were higher than those of late-lactating dairy cows. In terms of blood routine, compared with those of late-lactating dairy cows, the platelet distribution width (PDW) (P<0.01) of caudal artery of early-lactating dairy cows was extremely significantly decreased, the eosinophil count (P=0.04) was significantly decreased, the mean platelet volume (MPV) (P=0.07) tended to decrease, as well as the neutrophil count (P=0.07) tended to increase. To sum up, the mammary oxygen consumption is higher and mammary gland stress is stronger of early-lactating dairy cows compared with late-lactating dairy cows, and those results suggest that oxygen consumption regulation during early-lactation period may be a potential solution to reduce the metabolic stress of dairy cows during this period, which provides a new way of metabolic stress regulation in early-lactating dairy cows.