Using a standard split-step Fourier method, the coupled nonlinear Schrodinger equations were numerically solved. A theoretical investigation on the nonlinear propagation of two optical pulses in a photonic crystal fiber was presented. The role of pulse walk-off and intra-pulse stimulated Raman scattering on the propagation and compression of the signal pulse was highlighted. It was found that the signal pulse can be compressed through the cooperation by group velocity dispersion, self-phase modulation and cross-phase modulation, when the pump pulse with a wavelength of 800 nm is input in the anomalous dispersion region while the signal pulse with a wavelength of 740 nm is input in the normal dispersion region. Pulse walk-off not only leads to the degradation of the compression ratio and compressed peak power of the signal pulse, but also leads to a longer fiber length at which the width of the compressed signal pulse is minimum, and leads to the non-symmetry of the compressed signal pulse. It was also found that the quality factor of the signal pulse can be improved in the presence of intra-pulse stimulated Raman scattering.