Abstract: In order to investigate the effects of adding different additive proportions of oil palm leaves on the quality of fermented total mixed ration（FTMR） and the feeding effect of Hainan black goats, King grass was used as the main roughage to produce FTMR, and the ratio of crude to concentrate was 80︰20. Four groups were set up, namely 5%, 10% and 15% oil palm leaf groups and the control group, in which 5%, 10% and 15% oil palm leaf groups were added with 5%, 10% and 15% oil palm leaves, respectively. After 60 days of sealed fermentation, sensory evaluation was carried out, and the nutritional composition and fermentation quality of FTMR were determined. A total of 24 Hainan black goats at fattening stage were divided into four groups with six goats in each group. 5%, 10% and 15% oil palm leaves groups were fed FTMR supplemented with 5%, 10% and 15% oil palm leaves, respectively, while the control group was fed FTMR without oil palm leaves for 60 days. The growth performance and serum biochemical indexes were measured. The results showed that according to the evaluation criteria of Deutsche Landwirtschafts Gesellschaft（DLG）, all silage groups were grade 1. The crude protein content in the 5%, 10% and 15% oil palm leaf groups was significantly higher than that in the control group（P＜0.05）; the neutral detergent fiber content in the 10% oil palm leaf group was 45.71%, which was significantly lower than that of the control group（P＜0.05）, and the crude fiber and lignin contents in the 10% and 15% oil palm leaf groups were significantly higher than those in the control group（P＜0.05）. The daily gain of Hainan black goats in the 10% oil palm leaf group was higher than that in the control group（P＜0.05）. The volatile ammonia nitrogen/total nitrogen of FTMR in the 10% oil palm leaf groups was significantly lower than that in the control group（P＜0.05）. Except that the mass concentration of globulin in the 15% oil palm leaf group was significantly higher than that in the control group（P＜0.05）, and the creatinine concentration in the 10% oil palm leaf group was significantly higher than that in the control group and 5% oil palm leaf group（P＜0.05）, there were no significant differences in other serum biochemical indexes among all groups（P＞0.05）. In conclusion, the addition of oil palm leaves to produce FTMR would not reduce feed silage quality, and could improve the utilization rate of oil palm leaves. Under the conditions of this experiment, it was recommended to add 10% oil palm leaves.