【Abstract】Objective To investigate the expression of inducible nitric oxide synthase (iNOS) and p53 protein in hepatocellular carcinoma (HCC) and their relationship with angiogenesis. Methods Immunohistochemical method and image analysis technique were used to detect the expression of iNOS and p53 protein in tumor tissue sections of 59 HCC patients. Microvessel density (MVD) was counted by immunohistochemical staining with anti-CD34 antibody.Results ①The expression rates of iNOS and p53 were 81.4%(48/59), 64.4%(38/59) in HCC patients, respectively. The expression intensities of iNOS and p53 were 5 635±1 287, 3 352±873 in HCC patients, respectively. ②MVD was 32.5±2.73 in the tumor tissue of HCC patients. ③The expression of iNOS was correlated with the expression of p53 and MVD in HCC patients (P＜0.05); The expression of p53 was also correlated with the MVD in HCC patients (P＜0.05). Conclusion iNOS and p53 are highly expressed in HCC and may play a key role in angiogenesis of HCC.