The focus of this paper is to design an efficient and secure solution addressing the semi trusted issue in proxy re-signature schemes,i.e.,the proxy knows the re-signature key from user A to user B,so he is able to translate any signatures made by user A to user B,which damages the essential requirement(“non-repudiation” property) of proxy re-signature schemes.In this paper,the authors first define the security model for threshold proxy re-signature scheme,and then propose two threshold proxy re-signature schemes based on Ateniese-Hohenberger’s and Shao-Cao-Wang-Liang’s approach. The focus of this paper is to design an efficient and secure solution addressing the semi-trusted issue in proxy re-signature schemes, ie, the proxy knows the re-signature key from user A to user B, so he is able to translate any signatures made by user A to user B, which damages the essential requirement ( “non-repudiation ” property) of proxy re-signature schemes. This paper, the authors first define the security model for threshold proxy re-signature scheme, and then propose two threshold proxy re-signature schemes based on Ateniese-Hohenberger’s and Shao-Cao-Wang-Liang’s approach.