A non-Boltzmann distribution is constructed in terms of ion excitation-deexcitation equilibrium in plasmas, over which the rate coefficients of atomic processes are averaged, and an extended numerical model for charge state distribution of plasmas in collisional radiative steady state is established. The model is used to compute mean ion charge for various plasmas, ranging from low Z to high Z elements, as a function of electron temperature and density. Furthermore, the effects of non-Boltzmann distribution on mean ion charge and ion excited configuration population are investigated. The results show that the ion excited configuration population is evidently affected by the non-Boltzmann distribution.