Objective: To investigate the diagnostic value of acute appendicitis with atypical symptoms of multislice spiral CT scan. Methods: 25 cases confirmed by operation and pathology of acute appendicitis in patients with CT were retrospectively analyzed. Results: the CT manifestations of 18 cases of appendiceal thickening; 15 cases of appendiceal inflammation;8 cases of appendicular calculus; 1 cases of appendiceal abscess. Conclusion: multi slice spiral CT can clear diagnosis of atypical acute appendicitis, to provide effective help for clinical diagnosis and treatment.