This experiment was conducted to study the effects of dietary Artemisia annua extracts on milk performance and conjugated linoleic acid (CLA) content in milk fat of lactating cows. Fifteen Holstein dairy cows were randomly divided into 3 groups with 5 cows according to their body weight[(600±29) kg], milk yield[(22.8±1.8) kg/d], parity (2 to 3 parities) and lactation period[(158±3) d], and feeding trial were 40 days including 1 to 9 days for adaptation and 10 to 40 days for experimental stage. Cows in the control group were fed a basal diet, and the others were fed the basal diet supplemented with 96 (experimental group 1) and 160 g/(d·head) Artemisia annua extracts (experimental group 2), respectively. The results showed as follows:during the whole experiment stage, compared with the control group, the milk yield (the 24^th, 31^st and 40^th days), milk fat percentage, milk fat yield, milk protein percentage, milk protein yield, non-fat milk solid content and contents of saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, shot chain fatty, medium fatty and long chain fatty acid in milk fat of two experimental group were no significant differences (P>0.05); however, the milk fat CLA content of experimental groups 1 and 2 was increased by 30.7% and 38.6%, respectively, and there was a significant difference between the control group and experimental group 2 (P<0.05). In conclusion, dietary supplemented with moderate Artemisia annua extracts has no effect on the milk performance of lactating cows, but can increase the milk fat CLA content, and optimize the proportion of fatty acids in milk fat.