Abstract: To explore the effects of fermented total mixed ration（FTMR） on production performance, rumen fermentation parameters, serum immune indexes and fattening effect of cull ewes of Guizhou black goats, thirty-three healthy female Guizhou black goats with an average weight of（35.00±1.63）kg were selected as the study subjects. The experimental sheep were divided into 3 groups according to the random complete block design（RCBD）, with 11 animals in each group which was raised in a single column. The animals in group Ⅰ were fed commercially available pellet TMR, the animals in group Ⅱ were fed a conventional TMR, and the animals in group Ⅲ were fed FTMR. The pre-trial period was 10 d and the formal trial period was 75 d. Before the experiment, the test goats were weighed on an empty stomach, and then were weighed every 14 d to calculate daily weight gain（ADG）, dry matter intake and ratio of material to weight（FWR）, the cost of weight gain feed and weight gain benefit were calculated. At the end of the test, blood was collected from the jugular vein of the test goats. Serum immunological parameters（immunoglobulin A IgA, immunoglobulin M IgM, immunoglobulin G IgG, insulin-like growth factor IGF, interferon IFN, growth hormone GH, interleukin-2 IL-2, free triiodothyronine T3, free tetraiodothyronine T4） were measured. A 30 mL sample of rumen fluid was collected from each group of test sheep using the catheter method. The contents of total volatile fatty acids（TVFA）, ammoniacal nitrogen（NH₃-N）, acetic acid, propionic acid, butyric acid and pH value were measured. The proportion of main volatile fatty acids（VFA, acetic acid, propionic acid, butyric acid） in TVFA was calculated, and the acetic acid/propionic acid ratio was calculated. The results showed that the ADG was（196.43±36.28） g/d in test group Ⅲ, which was not significantly different from test group Ⅱ（P＞0.05）, but the ADG in the test group Ⅰ was significantly higher than that in the test group Ⅱ（P＜0.05）. The ratio of feed to gain in the test group Ⅲ was significantly higher than that in the test group Ⅰ（P＜0.05）. The cost of feed weight gain in the test group Ⅲ was RMB 8.87 yuan/kg, which was RMB 6.58 yuan/kg and RMB 0.22 yuan/kg lower than that in the test group Ⅰ and the test group Ⅱ, respectively. The weight gain benefit in the test group Ⅲ was RMB 370.16 yuan/goat, which was RMB 51.91 yuan/goat and RMB 25.41 yuan/goat higher than that of test group Ⅰ and test group Ⅱ, respectively. There were no significant difference in dry matter digestibility among the test groups（P＞0.05）, but the digestibility of crude protein, neutral detergent fiber and ether extract in the test group Ⅲ was higher than that in the test groups Ⅰ and Ⅱ（P＞0.05）. There were no significant difference in ruminal fluid pH value, TVFA content, the percentage of propionic acid, butyric acid in TVFA, and ethylene to propionic acid ratio among the test groups（P＞0.05）, but NH₃-N content in the test group Ⅰ was extremely significantly higher than that in the test group Ⅱ and test group Ⅲ（P＜0.01）. The IgA content in the test group Ⅲ was extremely significantly higher than that in the test group Ⅱ（P＜0.01）, but there were no significant differences in other immune indexes among the groups（P＞0.05）. The results indicated that feeding FTMR could improve nutrient digestibility, enhance humoral immune function, promote growth and development of Guizhou black sheep cull ewes, reduce the weight gain feed cost, and improve economic benefits of fattening.