The invention provides an HTTP message rewriting method and device. The method may comprise that a pre-configured rewriting parameter corresponding to a received HTTP message a header field, corresponding to the rewriting parameter, in the HTTP message are determined; a dynamic value of the rewriting parameter is determined; and the header field is rewritten according to the dynamic value. According to technical schemes of the invention, when the value of the header field which needs rewriting changes dynamically, the rewriting correctness by a load balancing device is ensured, and the HTTP message is rewritten dynamically.