Abstract: Objective: We intend to evaluate the application of low dosage multi-spiral CT (MSCT) combined with multiplanar reconstruction in the preliminary diagnosis of acute appendicitis in children. Methods: We performed low dosage MSCT scanning on 45 cases of children with acute appendicitis confirmed by operation and pathology. The imaging features were manifested through multiplanar reconstruction technology. Results: The effective radiation dosage of CT was (2.66±0.39) mSv; among the 45 cases, 22 cases were acute simple appendicitis; 15 cases were purulent with peripheral exudation, 4 cases were perforated gastroenteritis; 5 cases were gangrenous gastroenteritis, 3 cases were perforated gastroenteritis; 3 cases were appendiceal abscess. MSCT multiplanar reconstruction showed 32 cases of appendiceal enlargement, 25 cases of fecal calculus, 18 cases of liquid gas accumulation, 11 cases of fat stripe around appendix, 28 cases of intestinal wall thickening in ileocecal region, 30 cases of intestinal congestion, 33 cases of enlarged lymph nodes, 5 cases of peritoneal thickening, 3 cases of appendiceal abscess, 7 cases of appendix perforation and extraluminal free gas, and 12 cases of abdominal and pelvic effusion. Conclusion: In the preliminary diagnosis of acute appendicitis in children, the application of low dosage MSCT combined with multiplanar reconstruction not only holds the advantage of smaller dose and lower radiation, but also proves to be simple and accurate with lower rate of missed diagnosis and misdiagnosis. This technology showed significant application value, we suggest that it can be promoted to be apllied in guiding surgeons to formulate optimal operation plan.