In this paper, a novel approach of miniature tri-band microstrip bandpass filter is design for the application of GSM(1.8GHz),WiMAX(3.4GHz) and ) using Asymmetric SIRs and DGS to achieved the basic characteristic of microstrip filter such as low insertion loss, high selectivity, wider range of bandwidth, low group delay. The novel filter is design intentionally selecting the impedance ration(R) and length of the microstrip of the asymmetric SIRs and DGS is used to improve the coupling strength of the desired band. The measurement entities of the novel filter for GSM (1.8GHz), WiMAX (3.4GHz),) are insertion losses (S 21 ) are -0.07dB/-0.21dB/-0.12dB,and return losses (S 11 ) are -31dB/15dB/30dB respectively. The response of the filter was simulated using An soft HFSS Simulator.