Abstract: 【Objective】 The purpose of this study aims to test the main parts of urtica simulating smooth muscle movement, and to explore its possible receptor mechanism. 【Methods】 The biological signal processing system was used to monitor the effects of aqueous extract from urtica prickle or inner stem (without prickle) on the isolated small intestinal smooth muscle of mice. 【Results】 A 2-fold increasing concentration (0.1% - 3.2%) of prickles increased the intestinal contract amplitude, tension and peak in a dose-dependent manner (P < 0.05), but had no effect on contract frequency (P > 0.05); When the concentration of inner stem reached 0.4%, the contract frequency of the small intestine was reduced (P < 0.05). The contract amplitude, tension, and peak of the small intestine were significantly increased (P < 0.05) after 0.8% prickle administration, but the same dose of inner stem had no effect on the small intestine contraction (P > 0.05). The combination of M-receptor blocker ATr and 0.8% prickle significantly reduced the contraction (P < 0.05). 【Conclusion】 The prickle of urtica can promote the smooth muscle of the digestive tract, and the effect may be partly achieved by activating M-receptors.