In this paper

we present a heuristic algorithm based on graph-coloring and strategy of mobile station selecting serving cell to solve the wavelength-assignment problem which is a sub-problem of Routing and Wavelength Assignment（RWA） problem in Optical Transport Network（OTN）. We provide the process diagram

pseudo-code and designe the parameters to show the performance compared with other wavelength assignment algorithms. The experimental results show that the failure rate of wavelength assignment would reduce about 4%

and the increases of wavelength and regenerator are just 0.5%

which are under the constrain of wavelength-continuity and minimal number of wavelength and optical regenerators. This algorithm satisfies the application of network construct.