Abstract: From the beaches of Hainan sea area, mangroves and fishing wharf, production of salt beaches, rivers into the sea, a total of more than 40 isolated strains of yeast were obtained using the medium for isolation of Rhodotorula. A high-yield carotenoid which is Rhodotorula strains was screened through identification of morphological and physiological tests as well as the production of carotenoids.The strains in 2% glucose, 2% peptone, 0.3% yeast extract, riboflavin 2 × 10-6mol / L, PH 4.5 medium at 28 ℃ oscillation (180rpm) were cultured for 72 hours, the cell biological production is up to 87.55 g / L, carotenoid production is up to 520 mg / L. It can be grown at 13% in high-salt and superacid PH1.0 medium. With the fish co-culture experiments, the results showed that cell concentration in the right conditions, the strains is non-toxic and symbiotic to fish, indicating a good prospect.It is currently applied to salt-induced gene promoter Cloning and salt-induced gene expression of exogenous proteins (such as antimicrobial peptides) of the marine Rhodotorula Construction.