Objectives The effects of modified Dachaihu decoction combined with sodium selenite VE powder on treating the pig yellow fat disease were verified to provide reference for the prevention and treatment of this disease in clinics with traditional Chinese veterinary drugs. Methods 20 pigs aged 110 days with (47.1 ± 1.21) kg and naturally infected with yellow fat disease in a pig farm in Chongzuo City, Guangxi Zhuang Autonomous Region were selected and randomly divided into four treatment groups including the experimental group A, the experimental group B, the experimental group C, and the experimental group D, with 5 pigs in each group. The experimental group A, B, and C was given the low (40 g/d), medium(60 g/d), and high dose (80 g/d) of Dachaihu decoction combined with 100 g sodium selenite VE powder,. The experimental group D was only fed with 100 g sodium selenite VE powder, with a treatment period of 10 days and a trial period of 15 days. The effects on treating the pig yellow fat disease and prognosis were evaluated. Results The rate of recovery in the four groups was the same on the fifth day after administration, all at 60%. The rate of recovery in the experimental group C was the highest on the 10th day after administration, reaching 100%. The rate of recovery in the four groups on the fifth day after drug withdrawal was 100%. The average daily weight gain and the average daily feed intake of pigs in the experimental group B and C significantly increased by 13.22% and 16.68%, 3.43% and 4.39% compared with that in the experimental group D. The feed-to-gain ratio of pigs in the experimental group C was significantly lower than that in the experimental groups A and D, with reductions of 0.31 and 0.53, respectively. Conclusions When the dose of modified Dachaihu decoction was 80 g/d combined with 100 g sodium selenite VE powder, the best effect was achieved in treating the pig yellow fat disease, and it can improve the prognosis and production performance of pigs infected with yellow fat disease.