Abstract: The microstrip hairpin bandpass filter has been widely used in RF and microwave field for its compact structure and steady performances. This paper studies a hairpin bandpass filter with high selectivity by using ADS and the passband range of the filter is 2 ~3GHz. Compared with traditional hairpin filters, microstrip lines of a quarter wavelength are used in both input and output of the filter, which improves the stopband rejection of the filter by adding transmission zeros in the parasitic passband. In addition, a microstrip line of half wavelength is added on the resonator to improve the selectivity of the hairpin bandpass filter by generating a pair of transmission zeros at the two sides of the passband. Finally, the filter is made for testing and the testing results show that the filter has a good selectivity.