Abstract: Objective: To investigate the value of multi-slice spiral CT (MSCT) signs in differential diagnosis of pathological types of acute appendicitis. Methods: 78 patients with acute appendicitis confirmed through surgery and pathology in our hospital from October 2018 to September 2019 were retropectively analyzed. All patients underwent multi-slice spiral CT examination before operation while some patients with unclear appendicitis were performed curved surface reconstruction (CPR), then we analyzed the differences of MSCT signs in different types of appendicitis. Results: Among the 78 patients, 28 were simple appendicitis, 33 were suppurative appendicitis and 17 were gangrenous appendicitis. In the variance analysis, the difference between the appendiceal lumen diameter and the peripheral fat density in the three pathological types of appendicitis was statistically significant. In Spearman's rank correlation analysis, the P values of periappendiceal exudation, appendiceal bezoar, extraluminal effusion, mesangial thickening and intraluminal effusion were all less than 0.05, but their Rs values were different. Among them, periappendiceal exudation and mesangial thickening showed strong correlation with appendiceal typing. Conclusion: MSCT showed that signs including appendiceal lumen diameter, peripheral fat density, mesangial thickening and periappendiceal exudation held quite strong clinical guiding significance in the differential diagnosis of pathological types of acute appendicitis.