The Photonic crystal fiber-based stimulated Brillouin scattering coupled equations are solved by the method of fourth-order Runge-Kutta formula and characteristics. Pulse delay and broadening of the Stokes pulse are studied in different PCFs under the same Stokes wave intensity and the characteristics in the small core PCFs for different ratio are investigated. The simulation results show that small core PCF has better time delay and the smaller the ratio is, the larger the time delay is, and the maximum pulse broadening factor is accordingly larger.