Cubic spline and implicit iteration methods are used to solve the partial differential equations discribing the problem of substrate and microoganisms coupling transport in porous media. The results indicate that the scheme is appropriate to solve the nonlinear diffusion equations in witch convection dominates, and the final results are good. By the numerical analysis, the transport behaviours of microoganisms in porous media are generally understood. Moreover, the effects of every parameters in the systems are also ascertained.