Abstract: To investigate the effects of adding betaine to the diet on antioxidant function and meat quality of Tibetan Chicken, 180 30-week-old healthy Tibetan breeder hens with similar body weight during the egg-laying period were randomly divided into 3 groups: control group, experimental low-dose group and experimental high-dose group. In each group, there were 6 replicates with 10 chikens in each replicate. The hens in the control group was fed basic diet, and the hens in the experimental low-dose group and high-dose group were fed basic diet supplemented with 1 000 mg/kg and 3 000 mg/kg betaine, respectively. The pre-trial period lasted for 7 days, and the trial period lasted for 49 days. At the end of the experiment, antioxidation related indexes（the activities of superoxide dismutase SOD and Glutathione peroxidase GSH-Px and the content of Malondialdehyde MDA） in serum, liver, the rate of drip loss, cooking loss of chest muscle and leg muscle and meat color（brightness, redness and yellowness）, shear force and texture（hardness and viscosity） in chest and leg muscles were determined. The results showed as follows: the activity of liver SOD in the high-dose group was significantly higher than that in the experimental low-dose group and control group（P＜0.05）; the SOD activity of chest muscle in the high-dose group and experimental low-dose group was significantly higher than that in control group（P＜0.05）; the content of MDA was significantly lower than that in the control group（P＜0.05）; the SOD activity of leg muscle in the experimental low-dose group was significantly higher than that in the control group（P＜0.05）; the GSH-Px activity of leg muscle in the high-dose group and experimental low-dose group was significantly higher than that in the control group（P＜0.01）; the chest muscle brightness（L^* value） in the high-dose group and experimental low-dose group was significantly lower than that in the control group（P＜0.05）, but there was no significant difference between the high-dose group and the experimental low-dose group（P＞0.05）; the hardness of chest muscle（raw meat） in the high-dose group was significantly lower than that in the control group（P＜0.01）, but there was no significant difference between the high-dose group and the experimental low-dose group（P＞0.05）; the hardness of leg muscle in experimental low-dose group（raw meat） was significantly lower than that in control group（P＜0.05）; there were no significant differences in the activities of SOD, GSH-Px and the MDA content in the serum, the GSH-Px activity and MDA content in the liver, the GSH-Px activity, dripping loss rate, cooking loss rate, redness（a^* value）, yellowness（b^* value）, shear force（cooked meat and raw meat）, hardness（raw meat）, and viscosity（raw meat） in the chest muscle, and the MDA content, dripping loss rate, cooking loss rate, brightness（L^* value）, redness（a^* value） and yellowness（b^* value）, shear force（cooked meat and raw meat） and viscosity（raw meat） among the three groups. The results indicated that betaine added to the diet of Tibetan chickens could improve the antioxidant function and muscle quality of Tibetan chickens to some extent, and there was no significant difference in antioxidant function and muscle quality between high and low doses of Tibetan chickens.