Abstract： In order to effectively solve the problem of the signal quality degradation caused by the physical layer impairments in the transparent optical networks, the RWA algorithm of adaptive impairmentaware routing and wavelength assignment based on multiparameters constraint was proposed. According to the current state of the network in the process of routing, the weights of the physical layer multiconstraint parameters were adjusted dynamically to select the optimal light path. Meanwhile, the wavelength ordering problem was converted into finding the shortest Hamilton circuit in wavelength assignment, by utilizing an offline integer linear programming model to search the optimal wavelength order. Taking linear and nonlinear physical layer impairments into consideration in both the routing and wavelength assignment process, the quality of transmission can be ensured. The simulation results show that the proposed algorithm can reduce the blocking probability of the network, improving the blocking caused by the quality of light paths.