In this project, we have proposed an efficient re-routing algorithm by dynamic routing in Bi-directional WDM optical network. In wavelength division multiplexing network, a heuristic algorithm is used for routing and wavelength assignment. The main objective of this is to minimize the requirement of wavelength and hop length between S-D nodes in the traffic. In this project we have to considering a wavelength routed WDM optical network and then implementing Heuristic algorithm on it. We have to divide our work mainly into two phases. In the first phase, existing routing is performed using Dijkstra's algorithm and in second phase of algorithm proposed algorithm is performed to reduce the number of wavelengths required in the first phase of the network which minimizes the hop count of each route.