With the high-speeding development of the ultrashort laser pulses techniques, the stability of the soliton propagating in the dispersion-shift fiber has been becoming the topic in high speed optical communication system. From the nonlinear SchrÖdinger equation, in this paper we discuss a quasi soliton specific solution without distortion which has the stable propagating property, then simulate the waveform about these quasi solitons numerically, and more, by modifying the structure parameters of the fiber the width of these quasi soliton pulse can be adjusted and the soliton communication system can be optimized finally.