Abstract: Aiming at the problem of common neutral treatment process of wastewater, which was limited to a single reactor, this paper proposed a new model method, which contained neutralization pool, regulating pool and accidental pool.It was modeled by the neutral reaction mechanism, and used numerical methods Runge-Kutta method to solve the model after setting initial condition. This software was developed by algorithm and displayed by dynamic effects，real-time data and historical curve through a friendly interface. Simulation test showed that it could truly simulate the neutral process of sewage treatment plants,which used for teaching and experiments, and helped students to familiar with the sewage treatment process and finish control experiments.

Key words: Neutral process,Mathematical modcl,Simulation software