The third generation wave model WAVEWATCH is applied to simulate the wind wave generated by cold wave in Yellow and East Sea, and then the distribution of ship speed loss is approximately calculated by using the simulated wave height, wave period, etc. The calculated speed loss is analyzed and validated by comparing with the observed speed loss on board. The results show that WAVEWATCH can preferably simulate and reflect the distribution of wind waves, and the calculated speed loss is totally less than the observed speed loss.