A novel SiPM sensor system suitable for internal PD detection in GIS was designed， which had obvious advantages such as low drive voltage， small volume and high photon conversion rate. The consistency of the new SiPM sensor system， photomultiplier tube （PMT） and high frequency current transformer （HFCT） of pulse current detection device for PD detection was verified through the PD light-electric joint test， and the validity of phase resolved partial discharge method on SiPM detection results was also proved. On this basis， the field installation mode of SiPM was studied and tested. The results showed that the SiPM sensor system could achieve excellent detection effect in the field application and provide technical support for the field application of optical measurement method.