Background: Background: To investigate the diagnostic value of multi-slice spiral computed tomography (MSCT) in the anatomical variation of left renal vein (LRV). Materials and Methods: The clinical and imaging data of 96 patients with LRV variation in our hospital from June 2019 to December 2022 were retrospectively analyzed, and the imaging manifestations, classification, and clinical significance were discussed in combination with the literature. Results: Among the 96 patients with LRV variation, 30 patients (30/96, 31.25%) were type I (annular aortic type), including 20 cases of type IA, 7 cases of type IB, and 3 cases of type IC. A total of 17 cases (17/96, 17.71%) were type II (complete retroaortic type), with 15 cases were type IIA and 2 cases were type IIB. There were 52 cases (52/96, 54.17%) of type III (abnormal reflux type), with 32 cases of type IIIA and 20 cases of type IIIB. There were 15 cases (15/96, 15.63%) of type IV (delayed confluence type). Taken together, 18 of the 96 patients (18/96, 18.75%) had both types of variants, including 10 cases with other types of variants accompanied by delayed confluence of the LRV, and 5 cases with other types of variants combined with abnormal reflux. Conclusion: Fully understanding the anatomical variation of renal vein before operation is of great guiding significance for the selection of renal transplant donors, and helps to formulate the best renal surgery plan, guide the correct treatment of renal vein before operation, avoid renal vein tear, bleeding, miscut and misligation, and reduce surgical complications.