AIM: To explore a method for quantitative assessment of hepatic functional reserve by combining computed tomography (CT) volumetry with CT grading of liver cirrhosis before liver resection in patients with hepatocellular carcinoma.METHODS: CT images of 55 patients undergoing liver resection were studied prospectively. The degree of liver cirrhosis was referred as "CT grade" and the percentage of remnant liver volume (PRLV) [PRLV = predicted RLV/predicted total liver volume (PTLV) × 100%;PTLV (mL) = 121.75 + 16.49 × body mass (kg)] were calculated by adding slice by slice of CT liver images.The postoperative RLV, pathologic stages of liver fibrosis in non-tumor area and survival time in these cases were analyzed.RESULTS: There was a significant difference in survival time between the group with PRLV ≤ 50% and the group with PRLV ＞ 50% (χ2= 4.988, P = 0.026), and between the group with CT grade 0/1 and the group with CT grade 2/3 (χ2= 5.429, P = 0.026). With combination of the both parameters, an oblique line was identified according to the distribution of 32 survivors versus 23 deceased subjects. The mortality rate above the line was 7.1% (1/14), and that below the line was 53.7% (22/41),indicating a significant difference between the two rates (χ2 = 9.281, P = 0.002, P ＜ 0.05).CONCLUSION: PRLV and CT grades are significantly correlated with hepatic functional reserve. The predicted line using these two parameters is useful in candidates undergoing liver resection for judging hepatic functional reserve.