Objective To explore the prognostic risk factors of unsuspected gallbladder carcinoma after cholecystectomy, provide guidance for the treatment of those patients and improve the overall prognosis. Methods All patients with incidence gallbladder carcinoma who underwent reoperation at our hospital from 2008 to 2016 were collected. The related risk factors were analyzed by Kaplan-Meier single factor and Cox multivariate regression analysis, the difference of measurement data was measured with ttest. The χ2 test was used to measure the enumeration data. Results A total of 80 patients of unsuspected gallbladder carcinoma was enrolled, including 18 males and 62 females, aged 3080 years old. The overall survival time ranged from 1 to 89 months. The median survival time was 13.0 months. The 1, 3, 5 year survival rate was 59.9%, 41.7% and 33.4%, respectively. The results of univariate analysis showed that the postoperative survival time was related to the T stage, grade of pathology, the residual disease, the second postoperative N stage and margin status, whereas no relation with the secondary operation interval time, age and gender. The results of multivariate analysis showed the prognosis of patients was influenced primarily by the residual disease and the margin status of the secondary operation. In addition, we found that the second operation interval time was an important prognostic factor for patients with residual disease. Conclusion Residual disease and surgical margin status are important factors influencing the prognosis of incidental gallbladder carcinoma. For patients with residual disease, early radical resection should do as soon as possible. Standardized medical records and pathological reports play an important role in reoperation decision making.