Abstract: The broad-band UHF antenna used for Partial discharge(PD)detection needs to be fitted in the metallic shell in order to shield from the external radio interference, which makes the antenna characters change, leading to the fact that the antenna broadband character can not meet the requirements of the PD signal measurement. This paper presents a novel approach to improve the Voltage standing wave ratio(VSWR) by adding absorbing materials in the shell, and simulates the characters of the antenna by Ansoft HFSS. Moreover, the influence of different absorbing material dimensions on the antenna characters is analyzed. A PD detection broad-band UHF antenna with metallic shell is designed and experimentally tested. The analysis results show that the antenna directivity is changed and the antenna gain is enhanced,and the VSWR deteriorates with the metallic shell. By adding the absorbing material in the metallic shell to achieve better VSWR, the impedance bandwidth of the proposed antenna meets the requirements of the PD signal measurement broadband characters. This novel approach provides theoretical and practical guidance and reference for the design of actual PD UHF antenna.