Background: As a classification of appendicitis, complicated appendicitis has no standardized treatment for adults.Method: According to the related literature systematically searched on PubMed, Embase, Cochrane and Web of Science, we evaluated the efficacy of surgical treatment and conservative treatment for complicated appendicitis, especially focused on the outcomes about the length of stay, operation time, postoperative complications and unplanned additional intervention, in the literature. Result: A total of 14 studies were involved in the meta-analysis, including 845 patients in the immediate operation group (IO) and 756 patients in the conservative management group (CM). Compared with conservative treatment, the total hospitalization time was reduced by 1 day (WMD=-1.29, 95%CI [-2.42, -0.16], P=0.03<0.05). The incidence of unplanned additional intervention in patients undergoing emergency surgery is lower than that of conservative treatment (OR=0.18, 95%CI [0.11, 0.30], P<0.00001). Surgical patients are more likely to have complications such as wound infection (OR=2.41, 95%CI [1.08, 5.38], P=0.03<0.05) and intestinal obstruction (OR=4.14, 95%CI [2.21, 7.75], P<0.00001) than conservative patients. The incidence of abdominal abscess was lower than that of conservative treatment, and the difference was not statistically significant (OR=0.9, 95%CI [0.54, 1.47], P=0.66>0.05). Conclusion: Compared with conservative management patients, immediately operated patients have shorter hospitalization time and less unplanned intervention, which can significantly reduce the readmission opportunity of patients with complicated appendicitis and lighten the burden of follow-up and medical resource consumption.