Abstract: Effects of exogenous metallothionein (MT) on energy production and incretion of China Holstein cows were studied using 24 lactating cows, randomly allocated to groups A, B, C and D. MT was supplemented at 0.0, 6.0, 12.0 and 16.0 mg/capita, respectively, by intravenous injection. In groups B (during 1-30 d) and C (during 1-45 d), corrected milk yields were higher than that in group A. In group C during 31-45 d, milk fat percentage was significantly improved by comparison with group A. The INS serum content of group A was significantly lower than that of group B at 30 d; IGF-Ⅰor T₃ content of serum in group C was the highest at 45 d and the differences with group A were significant, while the IGF-Ⅰor T₃ of production in group D was inhibited. The ranges of variation of FSH or E₂ content in group C were the smallest of all the groups. The P content of in group B was significantly higher than that in other groups at 30 d, and the PRL content of group B was significantly higher than that in group A at 15 d. In groups B and C, MT contents of serum or milk were significantly higher than those in group A during the 30-45 d lactation period. In conclusion, the best choice was to supplement MT at 12 mg/capita for lactating cows by intravenous injection and a suitable time interval was once every 30-45 d.