The invention provides a special blade clamp with adjustable radial displacement. The special blade clamp comprises a clamping jaw, a clamp base, a driven sliding block, a driving sliding block, an adjusting part and a spring. An inner cavity is formed in the clamp base. The driving sliding block and the driven sliding block for a wedged mechanism which is arranged in the inner cavity of the clampbase. The inner cavity of the clamp base is used as a movement guide rail of the driving sliding block and the driven sliding block. The adjusting part is arranged on one side of the clamp base and used for adjusting the driving sliding block to move. The spring is arranged in the inner cavity of the clamp base and used for ejecting the driving sliding block and the driven sliding block to resetwhen the adjusting part is loosened. The clamping jaw is connected to the driven sliding block. The clamp can be adjusted according to actual blade deformation during secondary clamping after stress relief after blade rough machining, the effect that a blade is in a release state without clamp prestress when being clamped again is ensured, and thus deformation caused by uneven residual stress relief is reduced.