Miniaturized harmonic suppression type band-pass filter includes symmetrical electromagnetic band gap structure of microstrip composed of odd pieces of band gap unit. Loading fan-shaped microstrip branched structure on two sides of microstrip line obtains symmetrical band gap unit symmetrical in up down, and left and right. Coupling slot is introduced in a band gap unit in center of the symmetrical band gap structure. Thus, the band gap unit is divided into total identical two parts in horizontal direction to form two parts with identical resonance frequencies symmetrical to slot so as to establish resonant-type band-pass filter, as well as its center frequency and stopband characteristic. The coupling slot is equivalent to coupling capacitance. The disclosed band-pass filter possesses selected ultra wide stop band, and makes high order harmonics be fallen on range of stop band. Moreover, since effect of slow wave, size of filter is reduced greatly.