Abstract: A Joint Optimal Adaptive Protection Algorithm(JOA) is proposed to establish dependable connections for dynamic arriving connection requests in WDM networks. JOA first adjusts the cost of links according to the current state of network adaptively, and it then computes a pair of primary path and backup path for each connection request simultaneously. JOA attempts to perform optimization on the path-pair selection, and to achieve efficient resource utilization. Based on dynamic traffic with different load, the performance of JOA has been investigated against some traditional approaches via simulations. The results show that JOA has a better performance than other schemes.