Abstract: Researches of the wild Eucheuma resources were conducted in Eucheuma Nature Reserve of Hainan province in 2012. The results showed that there were 2 kinds of Eucheuma as Kappaphycus cottonii and dominant Betaphycus gelatinae in the Eucheuma Nature Reserve of Hainan province.The distribution area was 19.40 km2, where the average coverage and biomass of Eucheuma were 0.54% and 7.30 g/m2 respectively. The distribution area of Eucheuma in Qionghai was 14.35 km2, with the average coverage and biomass of Eucheuma of 0.55% and 7.85 g/m2, while that of Eucheuma in Wenchang was 5.05 km2, with the average coverage and biomass of Eucheuma of 0.49% and 5.78 g/m2. There were associated organisms 33 families and 50 species, with polychaetes 9 families and 14 species, mollusks 14 families 17species, crustaceans 9 families 18 species and echinoderms 1 families and 1 species. the average biomass and inhabit density were 6.38 g/m2 and 72.72 ind./m2respectively. The dominant species were Perinereis cavifrons, Cheiriphotis mediterranea, Ampithoe ramondi and Bemlos quadrimanus. The areas of the Eucheuma in the Eucheuma Nature Reserve of Hainan province had reduced too mach due to the herbivorous animals, the fishery activities, terrestrial pollution and coastal engineering.