This experiment aimed to establish the effects of Chinese herbal plant extracts compound (Astragalus root, Eucommia bark, Honeysuckle, and Quassic) to replace antibiotics on diarrhea rate, intestinal morphology, nutrient digestibility, and immunity of weaned piglets. In a 21 day experiment, 180 weaned piglets were randomly allocated to four dietary treatments, including a basal diet supplemented with 0 + 250 g/t oxytetracycline calcium and 50 g/t virginiamycin (control), 400 (T1), 500 (T2), and 600 (T3) g/t Chinese herbal plant extracts compound. The results showed that diets supplemented with Chinese herbal plant extracts significantly increased the number of Lactobacillus and Bifidobacterium in feces of weaned piglets, the villus height and ratio of villus height to crypt depth of jejunum and ileum, the levels of immunoglobulin G, immunoglobulin A, immunoglobulin M, interleukin-2, interleukin-4, total protein, albumin, tumor necrosis factor-α, and the apparent digestibility of energy, crude protein, crude fat, crude fiber, calcium, and phosphorus (P < 0.05). Diets supplemented with Chinese herbal plant extracts significantly reduced the number of Escherichia coli in feces and the diarrhea index (P < 0.05). In conclusion, dietary supplementation with Chinese herbal plant extracts compound preparation can improve intestinal morphology, feed apparent digestibility, and immunity and reduce diarrhea rate of weaned piglets.