Objective：To investigate the expression changes and the subcellular localization of heterogeneous nuclear ribonucleoprotein K (hnRNP K) in hepatocellular carcinoma (HCC) and cell line of different cell densities. Methods: The expression of hnRNP K in HCC was detected by immunohistochemical staining. The differential expression of hnRNP K in the HCC tissue (n=30) and paired paracancerous tissue was identified by Western blotting assay. The expression and sub-cellular location of hnRNP K in HCC cell line of different cell densities were determined by immunocytochemical staining and Western blotting assay. Results: Expression of hnRNP K was mainly detected in the nucleus of HCC cells. Twenty-one of the 30 hepatic cancer tissues had higher hnRNP K expression than the paired paracancerous tissues. Sixteen of the 20 HCC samples with HBV infection had an increased expression of hnRNP K; in the 10 HCC samples without HBV infection,5 had an increased expression of hnRNP K. Immunocytochemical staining and Western blotting assay both showed that the expression of hnRNP K was increased in the nucleus of HCC cells with the increase of cell densities （30%, 50% and 90% confluence）; the result of Western blotting assay also showed that there was no obvious change in hnRNP K expression in the cytoplasm of HCC cells of different cell densities（30%, 50%, 70% and 90% confluence）. Conclusion: The expression of hnRNP K is elevated in HCC tissues and has an increasing tendency in the nucleus with the increase of cell density. Infection of HBV may be associated with the up-regulation of hnRNP K in HCC cells.