A novel structure of miniaturized ultra-wideband (UWB) bandpass filter (BPF) with wide stopband has been proposed. By introducing defected ground structure (DGS), a short circuited coplanar waveguide (CPW) multiple-mode resonator (MMR) is constituted by a pair of improved complementary split-ring. Stepped impedance microstrip line is employed on the top plane to achieve broadband coupling and high selectivity. This configuration can obtain an UWB response between 3.1 and 11.3 GHz and a wide stopband region up to 24.2 GHz with perfect rejection characteristic of below 19.5dB. In addition, the effective overall size is less than 13mm×8mm. Design, simulation and measurement of filter prototypes are presented.