Objective: To investigate the effect of Weichangshu Tablet on gastric dynamics. Method : Fifty SD rats were divided into 5 groups randomly: normal control,L-Arg,L-Arg and cisapride,L-Arg and Weichangshu. Except the normal control group, the other four groups were injected with L-Arg intraperitoneally. All animals were orally given the same volume of medicine. Motilin content in plasma was determined by radioimmunoassay, and nitrate reductase was used for detecting serum level of NO. Result: Compared with L-Arg, L-Arg and weichangshu could increase plasma motilin and reduce serum NO effectively (P < 0.01). Conclusion : The possible mechanism of Weichangshu Tablet for promoting gastrointestinal motility: It can increase plasma motilin and reduce serum NO,and these changes may increase Ca2+ and promote the contraction of gastrointestinal smooth muscle.