Signals transmitted in the optical fiber are affected by attenuation, dispersion and nonlinear effects, resulting in distortion of the signal contained in the waveform or spectrum. Eigenvalue communication is used to overcome dispersion and nonlinear effects. In this paper, Darboux Transformation(DT) is used to synthesize soliton signal bearing information. By comparing with the analytical method and numerical method in Nonlinear Fourier Transform (NFT), the appropriate method is used to demodulate the recovered information. The eigenvalue communication method is verified by simulation. The factors such as the amplitude, pulse duration and sampling points of the eigenvalues in the transmission process are studied. The simulation results show that the communication distance can reach more than 2 000 km. On this basis, the selection range of the eigenvalues is optimized, so that the information carried by the eigenvalue can be demodulated more accurately at the receiver side.