Background Moymoya disease was a cerebrovascular condition, complicated by the recurrent stroke after surgery treatment. The accurate rate of good outcome and prognosis remained controversial. We aimed to summary and calculate the rate under the uniform definition of good outcome, evaluating the long-term effect of surgery. Methods Through systematically searching several databases, we included eligible studies measuring outcomes with the modified Rankin Scale (mRS), Glasgow Outcome Scale (GOS) and Kim’s category. Single group rates were transformed and synthesized to yielding the mean weighted probability. Sensitivity analyses were conducted to check the robustness of overall effect. Subgroup analyses were stratified by study type, population, age phase, presentation, surgical procedure and outcome measurement. Results The overall estimated rate of good outcome was 0.87 (95%CI, 0.84 0.90), with substantial heterogeneity. In the subgroup analyses, the outcome measured with GOS led to the highest rate of 91%, while Kim’s category the lowest rate of 82%. The combined bypass surgery group resulted in a higher good outcome rate of 0.92 (95%CI, 0.89 0.96) than the indirect bypass group of 0.83% (95%CI, 0.78 0.88). Conclusions MMD after surgical treatment could achieve a good outcome rate of 87%. Kim’s category reflected the functional outcome better, resulting in a good outcome rate of 82%. The combined bypass surgery led to better outcomes than indirect bypass.