In this study, we studied 5 kinds of algae using hot water and high temperature and high pressure to extract the crude algae extract by Ulva lactuca , Caulerpa lentillifera, Botryocladia leptopoda, Sarcodia montagneana and Eucheuma serra. The algae extracts was analyzed for total sugar, total phenols content, antioxidant activity and antimicrobial activity. The content of total sugar and total phenols are the best content in each group of Sarcodia montagneana. The antioxidant activity is also the best activity of Sarcodia montagneana. The algae extracts by high temperature and high pressure is better than hot water extraction of total sugar content, total phenols content, reducing power content and capacity to scavenge superoxide anion.The sea fungus group collected in February has higher total phenol content, reducing power, and chelating capacity of ferrous iron than other seasons. In addition, the results of antimicrobial activity showed that all groups of algae extracts had inhibition zone against of Vibrio alginolyticus. All groups of Ulva lactuca have an inhibition zone against of Vibrio parahaemolyticus. Therefore, the crude extract of Sarcodia montagneana extracted by high temperature and high pressure can be used in the future to further explore whether it can effectively enhance the immunity of white shrimp.