Objective To develop and validate a scoring system to predict the possibility of laparoscopic cholecystectomy (LC) conversion to laparotomy based on preoperative clinical data, and to establish a grading management model of surgery. Methods A retrospective analysis was conducted on the clinical data of 9 414 patients who underwent LC at Renhe Hospital and Huashan Hospital from June 2013 to June 2018. The patients were divided into two groups: the LC group (9 246 patients who successfully underwent LC) and the conversion to laparotomy group (168 patients who required conversion to open surgery). The data of two groups were compared, and the risk factors affecting conversion to laparotomy were screened out by single factor analysis of Chi-square test. Then, the risk factors were analyzed by multiple Logistic regression, and the pre-coefficient of each variable of the risk factors was assigned according to the established conversion to laparotomy possibility function. After calculating the score of each case, the difference in the actual conversion rate of each group was compared. The area under receiver operating characteristic (ROC) curve was calculated to evaluate the performance of the scoring system. According to the scoring system, LC surgical grading management model was created and verified. Results The following factors were identified as significant risk factors for conversion to laparotomy (P < 0.001): body temperature ≥ 38.5℃, frequency of acute cholecystitis ≥3 times, maximum thickness of gallbladder wall ≥ 5 mm, gallbladder neck stone incarceration, diameter of common bile duct ≥8 mm, and surgical experience ≤50 cases were the risk factors for conversion to laparotomy (P < 0.001). A score >3 points was associated with a high risk of conversion to laparotomy. Conclusions The LC scoring system and surgical grading management are reliable and effective tools for predicting and reducing the conversion rate of LC to laparotomy.