There is a bottleneck in the wavelengt h division multiplexed (WDM) fiber Bragg grating (FBG) sensor network.The conven tional WDM technique requires that each FBG sensor in the array must occupy a un ique spectral region.It seriously limits the maximum number or the measurement r ange of sensors in the network.In order to improve the performance of a WDM FBG sensor network,the Pareto-based multi-objective optimization technology is int roduced to design an optimal wavelength assignment in this paper.The two objecti ves are used to minimize the spectrum overlapping area and the bandwidth of the optical source.In this multi-objective model,there are a set of acceptable trad e-off optimal soulutions,called Pareto front.The non-dominated sorting genetic algorithm II (NSGA-II),which is one of the most efficient and famous multi-ob jective evolutionary algorithms,is applied for obtaining the Pareto front.The ac hieved Pareto front can help the decision maker to select a suitable solution.Si mulation reslts show that the Pareto optimzal solutions provide good wavelength assignments for various ovelapping spectra and the proposed approach is effectiv e in saving the source bandwidth and increasing the number of FBG sensors in the WDM FBG sensor network.