Abstract: The transmission characteristics of Gaussian pulses in optical fiber has been solved by analytical solutions, but that of hyperbolic secant pulses emitted by mode-locked laser only depend on numerical methods. In order to study the transmission characteristics of hyperbolic secant pulse with high-power in a single-mode optical fiber, the split-step Fourier method was used to analysis the transmission procedure of the hyperbolic secant pulse in single mode fiber with initial chirp 1.7 rad/s, dispersion length 0.64 m, nonlinear length 1.53m and length 1 m. The results indicate that the dispersion inductive spread of the hyperbolic secant pulse is consistent with the Gauss pulse, but its dispersion inductive frequency chirp is not vary linearly. It will also arouse the spectral oscillation if the input power is too high.