Abstract: The liquid fermentative condition of Trichoderma pseudokoning?? were studied through single factor and orthogonal design tests. The experimental results showed the optimized fermentative conditions are as follows: Culture medium formula is wheat bran 30g/L, corn meal 30g/L, sucrose 7.5g/L,KH2PO41g/L. The optimum fermentation period is 6d. The fermentation temperature and the initial pH-value of culture medium is 30±1℃ and 5.0~6.0 respectively. The mycelial dry weigh and the extracellular polysaccharides of Trichoderma pseudokoningii reached 5.272 g/L,0.622 g/L under the the optimized fermentative conditions.