Abstract: An optimized design method of waveguide band-pass filterer is presented in this paper. The proposed method is based on full-wave analysis, improved impedance inverter and adaptive micro genetic algorithm. Combined with the improved impedance inverter and full-wave analysis method, preferable initial values are obtained, especially in the broad band　case. An adaptive micro-genetic algorithm is supplied for the optimization. The numerical results indicate that with a smaller population size and fewer genetic generations, a better return-loss and pass-band micro-adjustment can be attained than the other methods. The hybrid method in this paper is better than the others for the waveguide band-pass filter especially when the amount of variable is comparatively large.