The invention discloses a GIS (Gas Insulated Switchgear) solid insulation life prediction method and device. Field GIS historical operating data and partial discharge data are obtained, so that extraction of the key aging state parameter of field GIS solid insulation is realized; therefore, a GIS solid insulation electric-field intensity simulation calculation model, a GIS solid insulation temperature-field simulation calculation model and a GIS solid mechanical stress simulation calculation model are pre-set; in combination with the defect damage value of the field GIS solid insulation obtained by the partial discharge data, calculation of the cumulative aging damage value of the field GIS in a service period is realized; finally, the life of the field GIS solid insulation is obtained bycalculation according to the pre-set relational expression of the aging degree of the GIS solid insulation and the device life probability density; therefore, the remaining life of the field GIS solidinsulation is predicated; the operating reliability of a power system is ensured; and unnecessary waste of resources is avoided.