Recently, design of Identity-based (ID-based) threshold signature schemes which are efficient and provably secure in the standard model has drawn great concerns. In this paper, an ID-based threshold signature scheme based on Paterson and Schuldt's signature scheme is presented. The proposed construction is proved secure in the standard model and its security rests on the hardness of the computational Diffie-Hellman problem. To the best of authors' knowledge, this is the first ID-based threshold signature scheme in the literature to achieve this security level.