Based on the theory of substrate permeation through the cytoplasmic membrane, and considering the effect of initial concentration of substrate, a new kinetic model of phenol degradation process was proposed. Comparing with the widely used Haldane model, which is greatly dependent on the initial phenol concentration, our model can be used to simulate the phenol degradation process in a wide range of initial,phenol concentration by using only one set of model parameters. Therefore, this new kinetic model has much more potential applications to industrial design and operation.