The invention discloses a light-weight automobile sound insulation pad separation layer cutting device, and relates to the field of automobile part processing. The light-weight automobile sound insulation pad separation layer cutting device comprises a supporting top plate, fixing mechanisms, supporting mechanisms, a template, a cutting device and a supporting bottom plate, wherein the supportingtop plate and the supporting bottom plate are oppositely arranged, the fixing mechanisms are arranged at the bottom of the supporting top plate in a sliding mode, the supporting mechanisms are arranged at the top of the supporting bottom plate in a sliding mode, each fixing mechanism comprises a first clamping device, a telescopic device and a fixing device, each supporting mechanism comprises a second clamping device, a sleeve, a sliding column and a fixing nut, the sleeves are arranged at the tops of the second clamping devices, the sliding columns are arranged in the sleeves in a sliding mode, the fixing nuts are in threaded connection with the sleeves, and the fixing devices can be used for fixing and supporting sound insulation pads.