Effects of ....3 series highly unsaturated fatty acids( ....3HUFA) on the development and survival of Chinese mitten..hand crab larvae, were studied by feeding with rot ifers enriched with two kinds of marine unicellular algae and the enrichment 50DE..G at early developmental stages and Artemia nauplii during postlarval developmental stages. The crab larvae obtained highest survival rate, 12. 00%, after fed with the rotifer treated with Chlorella, and then two groups treated with 50DE..G and Chaetoceros muelleri , 10. 67% and 9. 67% respectively, while the control group treated with baker.. s yeast is the lowest one, 3. 67%. The survival rate increased w ith increasing of the content of total lipid and ....3HUFA in the crab larvae, and the relative percentage content of ....3HUFA ( mainly eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) in the crab larvae may be affected by the content of ....3HUFA in its diets. The results suggest that EPA and DHA absorbed at the early developmental stages can influence the development and survival of the crab postlarvae.