Objective To improve the diagnostic level for small hepatocellular carcinoma ( SHCC )by exploring the characteristic appearance of SHCC on constract-enhanced 16-slice spiral CT multi-phase ( arterial, portal venous phase, and delayed phase ) scans. Methods The data on 53 patients with SHCC were retrospectively analyzed. All the patients received 16-slice spiral CT multi-phase scans, with scanning time of 34-40s at arterial phase, 65-80s at portal venous phase, and 4-6min at delayed phase. The constract of 85-95ml was intravenously injected at a velocity of 2.5-3 ml/s with a high pressure syringe. The enhancement patterns of SHCC were observed at different phases. Results 75lesions were found. The detection rate was 70.0% for plain scan, 97.1% for arterial phase, 82.9% for portal phase, and 87.1% for delayed phase, with a sensitivity higher in arterial phase than in portal phase and delayed phase. Conclusions Contrast-enhanced 16-slice spiral CT scans can fully reflect the enhancing characteristics of blood supply in SHCC, improving the detection rate and the accuracy of diagnosis. Key words: Small hepatocellular carcinoma; 16-slice spiral CT; Multi-phase scan