In order to obtain a high-quality ultrashort pulse light source, we combine the self-similar pulse with the grating pair, and analyze the evolution and compression process of the self-similar pulse in detail through a numerical simulation method. We first launch the Full Width at Half Maximum (FWHM) of 1 ps, energy of 45 pJ Gaussian pulses into a dispersion decreasing fiber to generate the chirp self-similar pulse with strong linear characteristic. Then we use the grating self-similar pulse chirp compensation compressor to obtained an ultrashort pulse with FWHM of 80 fs and peak power of 507.6 W. The compression quality parameter Q is 0.96, and the compression factor is 12.5. On this basis, we analyze the influence of the third-order dispersion in the declining fiber on the compression quality of the grating, and find that as the third-order dispersion increases, the compressed pulse quality will be significantly reduced. The results show that when the third-order dispersion effect in the system is small, high-power ultrashort pulses can be obtained by using self-similar pulses and grating pairs. This result is helpful for the acquisition of ultrashort pulses.