1 .In the culture of phytoplanktons the accumulative temperature at the climate of multipicatian, the relative growth constant, the generative interval, the biologial density at the climax and the biomass may be used as raising parameters. Among them, the relative growth constant has been calculated through the logarithum of the optical density.2, Tie solutions for raising phytoplankton were chosen from the best value of the raising parameter, Skeletonema castatum, Chaetoceros muelleri and Chaetoceros simptex var, calcitrans would be raised in the imitation f/2 solution. Carteria sp.would be raised in the solution of prescription No. 1. And Dicrateria zhajiangensis,Heteroloea sp.,Cryptomanas sp.，Chlamydomonas sp, and Platymonas suhcordiformis would be raised in th. solution. of prescription No. 2. The imitation f/2 solution can also be used for reserving some phytoplanktons.3. The amino--acid content of the phytoplankton and the dried flesh of Penaeus prnicillatus are as follow: Nitxschia closterium f. minutssiitima 34.6%，Chaetoreros simplex var. calcitrans 27.0%，Phaeodactylum triconutum 25.9%，Platymonas subcordiformis 22，9 %，Chlorella sp. 21.4%，Heterogloea sp. 20.0%，Dunadiella salina. 19.6%, Skeletonema costatum 18.3%，Dicrateria zhanjiangensis 10.5%,and Penaeus penicillatus 60.9%. The nutritive value of the phytaplanliton is lower than the dried flesh of the prawn. But Skeletonema costatum, Dicrateria zhanjiangensis, Heterogloea sp., Dunadiella salina.and Chlorella sp. contains methi-onine, which was absent in the dried flesh of the prawn, and Nitzschia closterium f，minutissima, Phaeodactylum triconutum , Chaetoreros simplex var, calcitrans,Platymonas subcordiformis and Skeletonema costatum are rich with lysine.4.By analysing the nutritive palue of the phytoplankton and the practical affect in rearing fry of the prawn, it is found that Nitzschia closterium. f. minutrissima,Phaeodactylum tricornutum, Skeletonema costatum，Chaetoceros simplex var.calcitr-ans and Platymonas subcordiformis are excellent foodstuffs in aquaculture.5.In spring a double concentration of the imitation f/2 solution is used for cultivation, and kept at the temperature under 10℃ . The phytoplankton of the species Dicrateria zhanjiangensis, Heterogloea sp.，Chlamydomonas sp.，Platymonas subcordiformis, Dunaliella salina.，Chlorella sp.，Nitzschia closterium f. minutrissima,and Phaeodactylum tricornutum can be reserved a year.