Objective To study the evaluation value of multi-slice spiral CT in patients with cholecystolithiasis and cholecystitis before laparoscopic cholecystectomy (LC). Methods A total of 48 patients with cholecystolithiasis and cholecystitis which diagnosed by CT or type B ultrasound from January 2015 to September 2016 were selected as the study group. Another 48 patients without gallbladder diseases which diagnosed by enhanced abdominal CT scan were selected the control group at the same time. The specific display rates and display scores of cystic artery and cystic duct were compared between the two groups. The anatomic structure and clinical variation were observed. Results Cystic ducts of all patients in the control group could be displayed, while there were 3 cases not displayed in the study group, and they all had acute cholecystolithiasis and cholecystitis. There were no significant differences between the two groups in the display rate and display score of cystic duct, the average display score, the variation rate of cystic duct route and the variation rate of cystic artery (P>0.05). Cystic arteries of two groups could be displayed, and the average display score of cystic artery in the study group was significantly higher than that in the control group (P＜0.05). Of the 96 patients, cystic ducts of 93 patients could be displayed, and the route was normal in 81 cases (87.10%) and variant in 12 (12.90%), including 7 cases of high cystic duct, 2 cases of right vagus bile duct formation, 2 cases of pronation in the right wall of the common hepatic duct and 1 case of low cystic duct. The cystic artery routes of 93 cases could be accurately displayed, among which 77 cases (82.80%) of cystic arteries were normal (type I a) and 16 cases (17.20%) were variant, including 5 cases of type Ib, 4 cases of type IIa and 7 cases of II b. Conclusion Carrying out multi-slice spiral CT examination in patients with cholecystolithiasis and cholecystitis before LC can effectively display the cystic duct and cystic artery, and find their route and variance, so as to provide important guidance for evaluation before LC.