Fermentation process for production of fodder yeast using dilute alkali solution of Cladophora were studied and optimized in this paper through single factor and orthogonal design experiments.The results showed that the optimal combinations were as follow: culture temperature was 30 ℃,the initial concentration of reducing sugar in fermentation broth was 3.5 g/L,inoculation level was 20% and(NH4)2SO4 5 g/L.Dry weight of yeast was 6.74 ± 0.83 g/L and the crude protein in fermentation broth could reach 15.12 g/L and the utilization rate of reducing sugar was 94.8% after 48 h of fermentation under these conditions.