Abstract: Objective：To analyze the expressions of arginase-2 (Arg-2) and inducible nitric oxide synthase (iNOS) protein in hepatocellular carcinoma (HCC) and the relations to angiogenesis. Methods：The expressions of Arg-2 and iNOS in tumor specimens from 158 postoperative patients with HCC were detected by using immunohistochemistry. The endothelial cells were immunostained with anti-CD34 antibody. The microvessel density (MVD) was quantified by Image-Pro plus 6.2.1 image analysis software. Results：In 158 HCC patients, the positive rates of Arg-2 and iNOS were 73.4% (116/158) and 83.5% (132/116), respectively. The expressions of Arg-2 and iNOS in HCC were positively correlated (r＝0.474, P＝0.000). The MVD was (283.92±130.69)/0.702 mm2 in 116 HCC specimens with positive expression of Arg-2, and (129.25±51.00)/0.702 mm2 in 42 HCC specimens with negative expression of Arg-2, and the difference was statistically significant (P=0.000). The MVD was (267±131.49)/0.702 mm2 in 132 HCC specimens with positive expression of iNOS, and (116±41.85)/0.702 mm2 in 26 HCC specimens with negative expression of iNOS, and the difference was statistically significant(P=0.000). Conclusions：The expressions of Arg-2 and iNOS are positively correlated in HCC tissues, which are both related to MVD. These results suggest that Arg-2 and iNOS may be involved in regulating microvascular angiogenesis in HCC.