Abstract: While cultur ing of pare nt prawn , an explosive epidemic disease happened during 1991 -1992 in a cult iva ting f isher y company in Shanghai .The mortality was ver y high .18 pr awns of r andom sampling were surveye d in si tu .The unif orm microorganism was found under microscrope in 17 pr awns .S -1 , S -2 st rains were obtained f rom haemolymph and liver of sick pr awn on plate PDA .During the infect ion experiment , the symptom was as same as that of the sick one .S -3 , S -4 str ains wer e isolated f rom the infectious pr awn .Al l the characterist ics of S -3 , S -4 were similar to S -1 , S -2 .S -1 ,S - 2 were proved to be the pathagenic organism, and identif ied to be Torulopsis mogi i .The kinds of effect ive medicine food(Pr awn -Ⅰ , Pr awn -Ⅱ)were developed for pr event ion and cure of the dise ase .