The invention relates to the technical field of clamps, in particular to an elastic clamp suitable for a thin-walled part. The elastic clamp for the thin-walled part comprises a clamp body, a cylindrical elastic sleeve, a pull rod and an inverted-circular-truncated-cone-shaped puller. A circular-truncated-cone-shaped boss is arranged on the clamp body. A center hole is formed in the boss. The elastic sleeve is located between the boss and the puller. Grooves matched with the boss and the puller correspondingly are formed in the two ends of the elastic sleeve correspondingly. The pull rod penetrates through the boss and the elastic sleeve and then is connected with the puller. By pulling the puller through the pull rod, the two ends of the elastic sleeve are evenly and elastically deformed, the thin-walled part is tightened through expanding, clamping force evenly acts on the inner wall of the whole part, the part is not deformed while the part is clamped firmly, and the machining quality is ensured. When the pull rod is loosened, the elastic sleeve rapidly rehabilitates under the action of contractility of the elastic sleeve and spring force, and thus the part is loosened and can be taken down from the clamp smoothly.