Abstract: OBJECTIVE To study and compare the effects of Xiao'er Jianpi plaster optimized prescription and original prescription, explore its possible molecular biological mechanism. METHODS The gastric emptying rate and small intestinal propulsion rate were used to detect the effects of the original and optimized prescriptions of Xiao'er Jianpi plaster on gastrointestinal function of rats with gastrointestinal dysfunction, and the content of motilin(MTL) in serum, total acidity of gastric juice, and stomach protease activity, the relative expression of MTL mRNA and protein in rat gastrointestinal tissues was determined by Western blotting experiment. RESULTS Both the original prescription and the optimized prescription of Xiao'er Jianpi plaster had promoting effects on gastric emptying and intestinal propulsion in rats with gastrointestinal dysfunction, and both had the same effect. The content of MTL in serum, total acidity of gastric juice, and pepsin activity of rats in the original and optimized formula of Xiao'er Jianpi plaster groups were significantly higher than those of the model group, and the expressions of MTL mRNA and MTL protein in the antrum and duodenum were significantly higher than those of the model group. The optimized formula promoted gastrointestinal MTL protein expression stronger than the original formula. CONCLUSION Both the original formula and the optimized formula of Xiao'er Jianpi plaster have obvious effects of promoting gastrointestinal motility, and their strengths are equivalent. The mechanism may be related to the promotion of MTL, pepsin secretion and the expression of MTL mRNA and protein in the antrum and duodenum.