The invention provides a signal receiving conditioner of a UHF partial discharge detecting system, comprising a broadband amplification module, a broadband detection output module, an intelligent switch module and a frequency-selecting conditioning-outputting module, wherein the broadband amplification module is used for performing band-pass filtering and signal amplification on received radio-frequency signals so as to obtain broadband amplification signals; the broadband detection output module is used for outputting the broadband amplification signals; the intelligent switch module outputsthe broadband amplification signals to the frequency-selecting conditioning-outputting module when being used in a specific interference environment; and the frequency-selecting conditioning-outputting module is used for mixing the broadband amplification signals and preset local oscillator signals, filtering intermediate-frequency signals obtained by mixing according to the frequency spectrum ofpartial discharge radiation signals, and extracting the partial discharge radiation signals from the intermediate-frequency signals. The signal receiving conditioner of the UHF partial discharge detecting system provided by the invention combines the broadband amplification detection technology and the mixing technology, extracts the partial discharge radiation signals from the radio-frequency signals in a detection field, and filters interference signals so as to enable the system to reach the optimum detection sensitivity and provide a hardware basis with complex anti-interference capability for the detection system.