In analyzing cancer patient survival data, the problem of competing risks is often ignored. This study used a competing risk approach to evaluate the efficacy of recombinant human type-5 adenovirus (H101) in patients with hepatocellular carcinoma (HCC) treated by transarterial chemoembolization (TACE). In this retrospective study, 476 patients were included. The cumulative probabilities of cancer-specific mortalities were analyzed by the Kaplan-Meier (KM) method and a competing risk model. Competing risk regression was used to assess the predictive factors for cumulative cancer-specific mortalities. Two hundred thirty-eight HCC patients received combination TACE and H101 therapy, and another 238 HCC patients received TACE therapy alone. For patients in the TACE with H101 group, estimated 1-, 2-, and 3-year overall survival (OS) rates were 61.0, 40.0, and 31.5%, respectively, while for patients in the TACE group, the estimated 1-, 2-, and 3-year OS rates were 55.0, 33.4, and 22.3%, respectively. The 1-, 2-, and 3-year cancer-specific mortality rates for patients in the TACE with H101 group vs. the TACE group were 37.3 vs. 42.0%, 55.7 vs. 63.5%, and 61.9 vs. 74.7%, respectively. Multivariate competing risk analysis established that a combination of TACE and H101 therapy was an independent factor in decreasing cancer-specific mortality. Compared with TACE therapy, patients who were diagnosed with unresectable HCC treated with combined TACE and H101 therapy had increased OS and decreased cancer-specific mortality. The survival benefit was more obvious in patients with elevated AFP, absence of metastasis, single tumor, enlarged tumor, and HBsAg-positivity.