Objective · To observe the effect of protease activated receptor 2 (PAR2) on the colonic motility in diabetic mice and investigate the mechanism. Methods · The momodel of type 1 diabetes mellitus was establishedintraperitoneal injection of streptozotocin. The smooth muscle strips and segments of colons were isolated. The effects of PAR2 agonist on colonic motility were observedmuscle strip tension contraction and colonic migrating motor complex experiments. The effect of small conductance calcium-activated potassium channel (SK3 channel) antagonist on it was also observed. Results · PAR2 agonist inhibited colonic motility and colonic smooth muscle was more sensitive to PAR2 agonist in diabetic mice. PAR2 agonist-induced inhibition was inhibitedSK3 channel antagonist. Conclusion · PAR2 activity in diabetic mice colons is significantly enhanced, which may inhibit colonic motility through SK3 channel.