The buffer layer is an important part of HV and EHV XLPE cable,influencing the cable mechanical properties and thermal performance.In recent years,most of cross-linked polyethylene (XLPE) HV cable faults in domestic were the buffer layer discharge.The designs of domestic cable buffer layer were summarized,with different types of high voltage power cables buffer layer effect analyzed.The possible reasons including materials,running in water,buffer layer design were exposed.With the analysis of three typical cases,the design hidden trouble and the buffer layer discharge problem were exposed to provide effective reference for cable design and cable fault analysis.