A cobweb topology sensor network was designed to meet the high requirements of large structure health monitoring on the reuse capacity and maintenance cost of fiber Bragg grating sensor network.In this structured network, Wavelength Division Multiplex(WDM) is used to increase the multiplexing capacity of the network, and the model based on gated cyclic unit is optimized to demodulate overlapping wavelengths.The new sensor network designed has high network reliability and network reuse capacity. Part of the structure of cobweb network is selected for experiment, and four kinds of fault conditions are designed for comparison. Through the four kinds of fault conditions, the signal can be effectively transmitted, which proves that the cobweb network has high reliability.In this paper, the four cases are summarized and summarized in the form of a table. The table shows that in these four cases, the network can still be used normally and has a high reliability.By improving the network structure of the demodulation model, the recognition accuracy of the model is increased, and the well-trained model is used to demodulate the spectra with different overlapping degrees. In 89.9% cases, the root mean square of the model is less than 1 PM, which proves that the improved model can effectively demodulate the overlapping spectra, and greatly increases the network reuse capacity.The experimental results of demodulation are presented in the form of tables and pictures. It can be seen that the central wavelength of each sensor can be well identified and the physical variables can be obtained under the condition of different degrees of spectral overlap.The new sensor network can increase the reliability and reuse capacity effectively.