Objective To test the mechanical property of Small Intestinal Submucosa. Methods The mechanical property of SIS were tested by SHIMADZU AG20KNA material test machine. Results Group A Stress of yield point is 7.72±0.70MPA strain is 42.66±14.69% Group B Stress of yield point is 7.57±1.94MPA strain is 42.34±8.29% Group C Stress of yield point is 3.91±0.91MPA strain is 71.59±3.64%. Conclusion The shape of load-extension diagram of SIS is just like that of collagen. The yield point stress of SIS is one seventh to fourteenth to that of the ligament and tendon. SIS exhibited an anisotropic mechanical property. Both yield point and max stress of SIS in longitudinal direction are nearly twice bigger than those in circumferential direction. The yield point and max strain in circumferential direction are more than 70%.