For the past few years, whether there is any genealogical relationship between biochar C (BcC) and humus carbon (HC) has been a hot spot in both pedology and geochemistry and a scientific issue for urgent solution. BcC is a kind of carbon-contained material, transformed from bioactive organic matter in an environment high in temperature and low in or free of oxygen, while humus is a kind of carbon-contained polymeric compound formed as a product of microorganisms decomposing dead plants or animals in soil. This review covered works done by foreign and domestic researchers on the relationship between BcC and HC in the recent 20 years, especially the recent 10 years. The researches available suggested that BcC could be transformed into HC by microorganisms. But the work on paths of the transformation and comparison between BcC and HC in physical, chemical and biological feature is still insufficient. Advantages and disadvantages were analyzed of a variety of methods, such as chemical oxidation, molecule marker analysis, hydropyrolysis, thermo-chemical oxidation, UV-oxidation, and nuclear magnetic resonance (NMR), used in quantitative analysis of BcC. Detailed introduction was presented to the application of scanning electron microscopy (SEM), elementary analysis (EA), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), Pyrolysis-Gas chromatography-Mass spectroscopy（Py-GC-MS）and NMR to structural characterization of BcC. Feasibilities were also elaborated of exploring comparison in structure and transformation between BcC and HC.