Based on the analysis of the distribution of inversion layer carriers in MOS structure, the concept of surface layer effective density-of-states (SLEDOS) is proposed. Then a new charge control model suitable for both semi-classical and quantum mechanical theory is established in which the effects of inversion layer carrier distribution on surface potential are included. In this model, a newly developed efficient iteration method is introduced, which has high efficiency and satisfied stability. Based on the model, the effects of quantum mechanical effects (QMEs) on inversion layer charge density both in weak and strong inversion regions and the surface potential are studied. Model results are compared with the self-consistent solutions of Schrodinger and Poisson equations, which proves the high accuracy of the new model.