Abstract: The Geometric programming (GP) method is applied to tackle the optimum control problem of groundwater quantity and quality. The nonlinear programming is easy to solve through transforming nonlinear restraints into linear ones by using the GP method.In order to put the GP method into practical use for the one-dimensional steady groundwater quantity and quality control problem, the velocity factor is separated form the coefficient matrix of water quality equation. And, the concentration can be expressed in an explicit form, thus reducing the number of restraints greatly. The Avriel-williams method is used to treat the negative coefficient problem. The proposed example shows that the GP method is feasible and effective.