A (k; n) threshold proxy re-signature scheme distributes the re-signature key of the delegatee and the delegator. The re-signing ability to n proxies in a way that any set of k or more honest proxies can col- laborate to re-sign, while any set of k ¡ 1 proxies cannot. We propose two threshold proxy re-signature schemes with trust dealer, which are both proved secure in the standard model. Threshold proxy re-signature schemes are based on the Computational Di±e-Hellman (CDH) problem with- out random oracles. The schemes satisfy the properties of bidirectionality, non-interactivity, multi-use and private proxy. Meanwhile, the re-signature share generation and veri¯cation algorithms are non-interactive and e±cient.