Circulating cell-free DNA (cfDNA) is considered a promising entry point of liquid biopsy for the diagnosis of early-stage liver cancer; however, many studies have confirmed that the diagnostic efficacy of cfDNA alone is not stable, especially that quantitative test alone cannot well reflect the situation of tumor. More and more studies have shown that cfDNA is suitable for combined measurement of multiple indicators or combined measurement with other diagnostic markers for liver cancer. This article reviews the articles on combined liquid biopsy based on cfDNA published up to July 2021, summarizes the existing methods for combined measurement, and briefly describes the birth and research advances in combined diagnostic methods, so as to further clarify the significance and potential of combined liquid biopsy based on cfDNA in the diagnosis of early-stage liver cancer and thus provide ideas for taking better advantages of the diagnostic markers for liver cancer in the future.