Abstract: Based on the propagation equation used to describe the normalized amplitude evolution in the fiber,the evolution of super-Gaussian optical pulse propagating in the single-mode fiber has been investigated numerically.The results show that for an incident super-Gaussian pulse with steep edges,the evolution of its shape,frequency chirp,and peak intensity are different from those for an incident Gaussian pulse.Its shape undergoes a variation from near-rectangular,multi-peak,and finally to single-peak;its frequency chirp is not linear;and its peak intensity increases at first,then passing a maximum,and finally decreases monotonously.And these evolutions relate to the shape and frequency chirp of the incident super-Gaussian optical pulse.