In order to confirm that products of phenol degradation by natural cryptomelane are innoxious, the authors conducted qualitative analysis of organic products and determined TOC of solution, thus detecting the oxidation routes of phenol. The oxidation mechanism of phenol is inferred on the basis of some experimental phenomena. The results are as follows: first, TOC can be reduced by 88.7% after the oxidation of phenol wastewater for eight hours; second, oxygen in Mn(Ⅳ)—O bond in cryptomelane changes into O·after it donates two electrons to Mn(Ⅳ), and then O·oxidizes phenol and its resultants are adsorbed on minerals. Some important intermediates detected in GC-MS experiments are p-benzoquinone, 2-benzofuranol and 4,4 '-diol-1,1 '-biphenyl, and the reaction routes of phenol oxidation are deduced by these intermediates.