Based on modified nonlinear Schr?dinger equation,the differential equations for evolution of parameters of bright-soliton-like pulses in optical fibers were derived by using variational method,and the differential equations were numerically solved by Runge-Kutta algorithm. The result indicates that the third-order dispersion compresses or broadens the width,the initial chirp broadens the width,the thirdorder dispersion and initial chirp deduce shift of frequency and phase and bigger chirp. So small coefficient of the third-order dispersion and initial chirp is helpful to stable propagation of soliton-like pulses in fiber,and changing the symbol of the third-order dispersion is also helpful to propagation of bright-soliton-like pulses.