This paper presents the numerical method used to solve the nonlinear plasma fluid equations. We have developed a fluid plasma model for a microwave plasma CVD reactor used for diamond thin film deposition. This model solves the electron and ion continuity equations, momentum transport equation and the Poisson's equation. In these equations we have the problem of non-linearity which is solved using the Newton’s method. From these equations, the unknowns computed are electron and ion densities (ne,ni), and plasma potential (ψ). Then the impacts of the hydrogen pressure and microwave power density have been studied. Simulation results show a strong effect of these parameters on the species densities distribution in the plasma.