The invention discloses a tool for high-speed numerical control milling machining of a thin-walled part. The tool comprises a support, a support and two follow-up clamping devices oppositely arrangedon the support, wherein each follow-up clamping device comprises a first linear driving mechanism, a hollow shell, a heating mechanism, a gas supply mechanism, a deformation mechanism and a floating clamp, each deformation mechanism comprises a planar thermoplastic layer and an elastic outer layer wrapping the planar thermoplastic layer, and each floating clamp comprises cylinder bodies, floatingchucks, pistons, a second linear driving mechanism and a closed partition plate. According to the tool, the flexible clamping of the thin-walled part is realized, the thin-walled part can be effectively attached, the clamping deformation of the thin-walled part is effectively avoided, the machining quality of the thin-walled part is improved, clamping of different thin-wall parts can be realized,and the application range is wide.