Abstract: The paper measured and compared compositions of 19 fatty acids of six marine shellfish species in Zhanjiang, Guangdong Province of China, in summer and winter by using GC-MS, and the influences of climate changes in these two seasons on the fatty acids' composition and nutritional value were discussed as well. The results showed that the lipid content of the marine shellfish species studied were (0.110.01)%~(0.190.01)% (summer) and (0.150.00)%~(0.450.04)% (winter); saturated fatty acids were 35.15%~47.29% (summer) and 41.96%~45.99% (winter); monounsaturated fatty acids were 9.47%~17.68% (summer) and 13.62%~18.04% (winter); polyunsaturated fatty acids were 39.35%~48.56% (summer) and 36.255%~43.15% (winter). Therefore, SFA, MUFA and PUFA contents were significantly higher in winter than in summer, and the total lipid percentage was also higher in winter than in summer, but not significant.