The mathematic model for phenol-removing is set up based on the filter column testing and analysis of the phenol-removing effect of the sewage containing phenol through percolation of quarts-sand-layer. And it is proved that this model reflects the phenol-removing regularity not only of quarts-sand-layer objectively, but also of aquifer thruthfully by engineering practice. It can be used in the predication of the phenol concentration in the design of those wells which are built on the river bed or riverside. The phenol-removing mechanism of quarts-sand-layer and aquifer is also discussed in this paper.