Microbial lipid production was done in 300-L bioreactor using Rhodosporidium toruloides Y4 as the lipid producer and corn stalk hydrolysates as the feedstock.No detoxification procedure was involved for processing the pretreated biomass or the hydrolysates.There results were, lipid concentration 3.5 g/L, cellular lipid content >31% and lipid productivity 0.16 g/L /h.Ion chromatography analysis indicated that at the end of the culture, residual glucose, xylose and arabinose were 0.1 g/L, 0.7 g/L and 0.9 g/L, respectively.Gas chromatography analysis confirmed that the major fatty acid constituents of the lipid sample were palmitic acid, stearic acid, oleic acid, and linoleic acid.Our results suggested that microbial lipid can be produced using biomass hydrolysates as the feedstock and be used for biodiesel industry.