A new asymmetrical pulse pair method is proposed which can be used to suppress the pulse walk_off effect during the process of pulse compression by the cross phase modulation of pulse pair. By using asymmetrical pulse pair method and asynchronous coupling method, the suppressions of the walk_off effect have been investigated numerically. Results show that for an incident Gaussian pulse with peak power 10mW and full_width_at_half_maximum (FWHM) 5ps, we can obtain a compressed pulse with the compression factor 137, pedestal energy ratio 0122 and the peak power 116mW by adopting the asymmetrical pulse pair method.