The existing artificial anal sphincter clamping mechanism has the disadvantages of low biocompatibility and long response time. Based on the defecation mechanism and physiological structure， this paper discusses the design of a Novel Closed-link Artificial Anal Sphincter （NCAAS） clamping mechanism. The NCAAS clamping mechanism consists of three sets of interlaced clamping arms and a transmission mechanism based on groove cam swing rods. To study its biocompatibility and response time， the clamping force equation of the clamping arm was derived from the principle of virtual work， and the processing of the finite element in instantaneous dynamic simulation. During simulated stool control， the maximum clamping force of the NCAAS is 1.6 N， and the anorectal angle is in the range of 62.2°~95.2°， which meets the demands of human daily stool control mass. The weight of the NCAAS prototype is 55.19 g， with a height of 42.7 mm and length of 68.2 mm. The response time of the improved system is 7.25 s. An in vitro experiment with a pig colon verified the biocompatibility of the NCAAS， which draws the result of a 700 g controlled stool mass at an anorectal angle of less than 90°. The NCAAS is small and light， with better biocompatibility and a response time that is significantly shorter than that of traditional artificial anal sphincters.