Objectives The effects of compressed and fermented feed of chestnut made from chestnut leaves, bran, and EM bacterial liquid as a substitute for roughage on the growth performance of mutton sheep and economic benefits of farming were studied to provide a theoretical basis for its application in fattening mutton sheep and other ruminant animals. Methods 120 locally grown 3-month-old small tailed Xian lambs with an average body weight of approximately (15±0.89) kg in Qianxi County were selected and randomly divided into 2 groups, with 3 replicates in each group and 20 lambs in each replicate. Experiments were conducted simultaneously at two farms in Qianxi County, Hebei Province including LI Chunwei Farm in Baitazhai, Shaheqiao, and Longsheng Farm in Longwan Village, Santun Town. Lambs in the the control group were fed with basic feed, while lambs in the experimental group were fed with self-made compressed and fermented feed of chestnut leaves obtained by anaerobic fermentation of chestnut leaves and bran with a mass ratio of 8:2 through EM bacterial liquid, with a feeding period of 120 days. The daily feed intake of lambs in each group of was measured separately. The overall quality of the sheep herd was measured at the beginning and end of the experiment, and the profit was calculated based on the feed cost and the total weight gain of the sheep herd. Results The final weight, total weight gain, total material consumption, and average daily weight gain of lambs in the experimental group was significantly higher than that in the control group at Chunwei Farm, with a increase of 78.16, 77.38, 401.21 kg and 32.24 g/piece, respectively. The profit of lambs in the experimental group was 363.64 yuan per lamb, a significant increase of 118.24 yuan per lamb compared to that in the control group. The final weight, total weight gain, total material consumption, and average daily weight gain of lambs in the experimental group was significantly higher than that in the control group at Longsheng Farm, with a increase of 80.83, 82.32, 387.82 kg and 34.30 g/piece, respectively. The profit of lambs in the experimental group was 376.84 yuan per lamb, a significant increase of 124.24 yuan per lamb compared to that in the control group. Conclusions Using compressed and fermented feed of chestnut leaves instead of roughage can significantly improve the weight gain of lamb and economic benefits.