To tackle the problems of security stream exchange in the large-scale complicated network, this paper applies proxy re-signature technology for the first time to solve the flow exchange security issues, and proposes a proxy re-signature scheme based on trapdoor Hash function for stream exchange. Firstly, aiming at the key exposure problem of trapdoor Hash function for stream exchange, a new trapdoor Hash functions without key exposure (EDL-MTH) is put forward and its security is analyzed. Then, a new proxy re-signature scheme based on EDL-MTH is constructed and is proved against the chosen-message attack in the random oracle model. Furthermore, the performance of the scheme is analyzed contrast to the existing proven security proxy signature scheme, and the result shows the efficiency becomes more prominent while the scale of stream exchange is increased. Finally, a case study is provided to demonstrate its availability and performance in security stream exchange.