Taking the diffraction theory as the foundation,with the maximum output power representing the effect of optical limiter,expression of output power in optical limiter based on both nonlinear-refraction and nonlinear-absorption was derived.Rules of output power,limiting ability and the best position of medium to limit were analyzed in numerical method when the limiter was irradiated by continuous Gaussian beam.Results indicate that output power oscillates and weakens along with increasing input power when the nonlinear absorbtion is weak,but nonlinear absorption makes it′s period notably larger under high incident power range.Oscillation of output power disappears with nonlinear absorbtion strengthening.Strong nonlinear absorbtion makes the limiter still has very good limiting ability even when aperture′s linear transmittance exceeds 0.75.A fixed value will exist for every limiter,when the ratio of nonlinear absorbtion phase to refraction phase exceeds it,absrbtion raise the limiting ability,else reduce the ability.