Abstract: The high voltage FDS for XLPE cables of both overall and local thermal aging in different stages are detected, and the effects of various aging degree and different local aging section proportion are explored. Besides, by combining the changes of physical and chemical properties and mechanical properties of XLPE material in the aging process, the relationships between the macroscopical high voltage dielectric and the microscopical physicochemical properties are elucidated. Finally, the aging evaluation method of XLPE cable based on high voltage FDS is discussed. The results show that the high voltage FDS of cables with a certain degree of aging, whether overall or local aging, show the characteristics of delamination, which is due to the increase of polarization intensity caused by the destruction of polar groups and crystal regions caused by molecular bond breaking. Besides, the L of cable samples with overall and local thermal aging defects with a certain aging degree is greater than 1, and the L matrix can be used as the diagnosis parameter of cable aging phenomenon; nonlinearity η at higher detection voltage level (1.0U₀) is sensitive to the change of aging degree, and is less affected by the proportion of local defects, which can be used as the evaluation feature of cable aging degree. It can be determined whether the cable is partially aged by combining the value of η and the range of integral.