Most of the existing threshold proxy signature schemes were under the certificate-based public key systems. However, in these schemes, some revealed that the receiver cannot find out who signed the proxy signatures. In this paper, based on Schnorr's signature scheme, integrating the short secret key characteristic of the elliptic curve cryptosystem, we proposed a novel (t, n) threshold proxy signature scheme. Compared with the reported (t, n) threshold proxy signature schemes, our scheme can reduce the amount of computations and communications without a dealer. What's more, used our scheme, the original signer can know who generated the proxy signature and the receiver can certify the actuality of the group signers.