The invention belongs to the technical field of body area network node authentication and provides a method and a system for signature authentication based on an elliptical curve. The method comprises the following steps of initializing authentication parameters based on the elliptical curve; at a node A, randomly selecting (formula) as a private key, computing a public key QA=Dap=(QAx, QAy), storing the private key and publishing the public key (G1, G2, H, P, QA); at the node A, randomly selecting two integers m, wherein r belongs to ZP, and computing a signature value sigma' in an offline state; at the node A, recovering state information m and r and computing an online signature value r' of a message M; generating a complete signature sigmaM of the message M according to the signature value sigma' in the offline state and the online signature value r' of the message M which are obtained by computation, and sending the generated complete signature sigmaM of the message M to a node B; and at the node B, carrying out effective authentication of the signature on the complete signature sigmaM sent by the node A. according to the method and the system, the signature authentication based on the elliptical curve is realized, and the calculated quantity for signature and verification is effectively reduced and the signature verification speed is improved.