Effects of group velocity dispersion (GVD) induced chirp evolution and self phase modulation(SPM) induced chirp evolution as well as the combined GVD and SPM induced chirp evolution in the normal dispersion regime of single mode fibers are studied. We get analytic solution of GVD leading chirp and SPM leading chirp using Fourier transform algorithm. Numerical solution of the combined GVD and SPM leading chirp using numerical methods is obtained. The results show that chirped pulses can be compressed and dark soliton can be formed.