An arbitrated quantum signature scheme based on entanglement swapping is proposed in this paper. On the foundation of Bell states, the message to be signed is coded with a unitary sequence, and consequently the unitary sequence is used to calibrate the Bell states between the signer and the arbitrator, finally the signature is generated through quantum cryptography. Using the correlation states generated through entanglement swapping on the arbitrators side, the receiver can verify the signature through Bell measurement on his own side. In this scheme, anyone except the authentic signer cannot forge a legal signature and the true receiver cannot deny his recipient because the security of underling quantum cryptography and the participantsprivacy are effectively protected in this scheme.