Two compensating methods about solitons transmition systems at 40 Gb/s in a photonic crystal fiber are investigated. The maximum transmission distance of the system is calculated numerically by sliding filters and synchronic modulation technology. The maximum transmission distance increases evidently which occasionally is three times longer than before. The results show that the actions of high order dispersion, polarization mode dispersion, and high order nonlinearity are weakened by the two methods. The compensating effect of synchronic modulation technology is better than that of the other one. The capability of the compensated system is ameliorated, which is shown by eye patterns.