Objective To study the clinical significance of multi-slice spiral CT in portal vein imaging. Methods One hundred and thirty seven cases underwent enhanced scan with GE Light SpeedQX/i4 CT scanner were collected, including 41 cases of liver cancer, 20 cases of hepatic cirrhosis, 21 cases of cavernous hemangioma of liver, 9 cases of hepatic abscess, 6 cases of carcinoma of gallbladder, 14 cases of cholangiocarcinoma, 16 cases of pancreatic carcinoma, and 5 cases in normal. The results of portal vein images were reconstructed with three-dimensional software and analyzed. Results In 109 cases, portal vein, cranial mesenteric vein, and splenic vein were demonstrated successfully in the stage of portal vein: volume rendering images were clear in 84 cases, and maximum intensity projection images and multiplanar reconstruction images were clear in 109 cases. Forty-five cases of portal hypertension, 18 cases of opened collateral circulation, 15 cases of portal vein tumor thrombus, 1 case of splenic vein tumor thrombus, and 6 cases of large cavernous hemangioma were demonstrated successfully. Conclusion The portal vein imaging with multi-slice spiral CT can show the dissection and lesions of portal vein and its branches clearly, and can provide the clinical evidence for clinicians to formulate a treatment plan correctly.