ObjectiveTo evaluate therapeutic effect of the targeting recombinant adenovirus Ad-EAFP-PALB/r-Caspase-3 on primary hepatocellular carcinoma cells (HepG2) and subcutaneous implanted tumors of nude mice. MethodsHepG 2 cells, breast cancer MDA-MB-231 cells， and normal hepatic L-02 cells were infected with the previously constructed targeting recombinant adenovirus Ad-EAFP-PALB/r-Caspase-3, then morphological change was observed and apoptosis index was detected by cell morphologic assay. Tumor growth and pathological changes were observed after the implanted tumors model of nude mice were injected with the recombinant adenovirus. Results Both apoptosis and obvious apoptotic peak of cells were observed by flow cytometry (FCM) in HepG 2 cell group. The apoptosis index of MDA-MB-231 and L-02 cells was 0 and 7.3%, respectively, which were significantly lower than that of HepG2 cells (48.2%), Plt;0.01. The volume of subcutaneous tumor of nude mice was (0.26±0.31) cm 3 in HepG2 cell group, (0.25±0.15) cm 3 in MDA-MB-231 cell group， and (0.26±0.28) cm 3 in control group on two weeks after implantation of cancer cells, and no statistical difference was found among them (Pgt;0.05). The volume of subcutaneous tumor of nude mice was (0.53±0.12) cm 3 in HepG 2 cell group, (0.49±0.22) cm 3 in MDA-MB-231 cell group， and (0.54±0.13) cm 3 in control group on four weeks after implantation of cancer cells, and the difference was not significant among them (Pgt;0.05). But on eight weeks after implantation of cancer cells, the volume of tumor was (0.65±0.13) cm 3 in HepG 2 cell group, (1.27±0.32) cm 3 in MDA-MB-231 cell group， and (1.43±1.09) cm 3 in control group, which suggested that the growth of tumor in HepG 2 cell group slowed down significantly when compared with MDA-MB-231 cell group and control group (Plt;0.01), although the difference in the latter two groups was not significant (Pgt;0.05). The necrosis regions were found with lymphocytic infiltration and apoptosis cells in HepG2 cell group after injection of recombinant adenovirus Ad-EAFP-PALB/r-Caspase-3, but no pathological change of cells was found in control group after injection. It was found that the cells in MDA-MB-231 cell group were solidly arranged with small glandular lumenlike structure, marked cellular atypia, multinucleated tumor cells and megakaryocytic tumor cells, which was not different from that before injection. ConclusionThe targeting recombinant adenovirus Ad-EAFP-PALB/r-Caspase-3 induces the apoptosis of primary hepatocellular carcinoma in vivo and in vitro, which may provide new ways of targeted gene therapy.