Abstract: Microstrip hairpin stepped impedance resonator filter has found wide application in microwave communication system with the advantages of compact size，low cost，easily integrated and adjustable parasitic pass-band. This paper described X-band stepped impedance resonator band-pass microstrip filter with 8.1GHz center and a bandwidth of approximately 400 MHz, From 7.9GHz to 8.3GHz insertion loss is better than 3.5dB and the fluctuant range is less than 1 dB.The out-of-band rejection levels are larger than 50dB at 6.5GHz and 9GHz.The size of filter is 10mm*10mm.