Objective To explore the clinical value of multi-slice spiral CT in the detection of small intestinal lesions in patients with Peutz-Jeghers syndrome(PJS). Methods 30 cases of patients diagnosed as PJS were treated by transanal insufflation and indirect filling of small intestine. Then whole abdominal CT scanning were carried out as well as three dimensional reconstruction. 19 cases underwent oral endoscopy, and 13 underwent anal endoscopy. Evaluate the filling degree of small intestine, and calculate the detection rate of CT. Results There was a positive correlation between small bowel inflation score and small bowel grouping (P<0.001). The detection rate of CT was lower than that of the oral group (upper group of small intestine) (P<0.001). The detection rate of upper group small intestine and small intestine group was not statistically significant (P＞0.05). Conclusion The filling degree of transanal insufflation is not good for the 1-3 groups of small intestine but better for the 4-6 groups as regard to reliable diagnostic condition; CT transanal insufflation has a higher detection rate for the lesions needed clinical intervention, and has a guiding value for the choice of clinical endoscopic approach.