Abstract: This study was to determine the preventive effect of fermented Chimonobambusa quadrangularis shoot( FCQS) on diphenoxylate induced constipation in mice.The FCQS had more loosened fiber tissue structure than unfermented Chimonobambusa quadrangularis shoot( UCQS),which was more helpful to relieve constipation.After the mice were fed with FCQS for 9 days,the time consumption for their first black stool defecation was shorter than the control group and UCQS groups but longer than normal group and bisacodyl treatment group. The gastrointestinal transit of FCQS group was higher than control group and UCQS group,but lower than normal group and bisacodyl group. By observing the HE section of mice intestine,it was found that FCQS reduced the injury of intestinal tract suffering from constipation and alleviated the damages of the intestinal villi which were better than UCQS played. FCQS also can increase the serum levels of MTL( motilin),ET- 1( endothelin- 1),VIP( vasoactive intestinal peptide) and Ach E( acetylcholinesterase) comparing with the control group. These results showed that FCQS had good preventive effect on constipation.