The invention discloses a band-gap adjustable micro-strip ultra-wide filter, which is mainly used for solving the problems that the band-gap loading ultra-wide filter has out-of-band suppression difference, bigger band gap width and independent turning of double band gaps. The filter comprises a micro-strip medium substrate (1), a metal grounding plate (2), a multi-mode resonator (3), a pair of input-output interdigital micro-strip feeder lines (4), a defected ground structure (5) and a direct-current biasing circuit (11), wherein a T-shaped branch (6) is loaded in the center of the multi-mode resonator (3); a band gap resonator (7) is loaded on the lower surface of the multi-mode resonator (3); the band gap resonator consists of two symmetrical stepped-impedance resonators (71, 72) and a variode (10); and capacitance value of the variode (10) is controlled by adjusting the biasing voltage of the direct-current biasing circuit (11). The band-gap adjustable micro-strip ultra-wide band filter is small in dimension, narrow in band gap width, good in out-of-band suppression difference, is capable of realizing continuous adjustment of the first band gap, is capable of keeping the second band gap constant and can be used for a wireless communication system.