The fermentation conditions of producing lipase by Aureobasidium pullulans were studied and optimized.Methods: Temperature,initial medium pH and amount of inoculation were investigated by central composite design after the preliminary experiment was finished.Results: Temperature,initial medium pH and amount of inoculation were the significant effective factors on lipase activity in crude enzyme liquid.There was no interactive influence on lipase activity among temperature,initial medium pH and amount of inoculation.The regression model equation was obtained(R2= 0.9556).The optimum value of temperature,initial medium pH and amount of inoculation were 26.02℃,5.87 and 6.38% especially.Conclusion: The relationship could be explained by the regression model equation between lipase action and the temperature,initial medium pH and amount of inoculation.It could predicate and guide better the process of producing lipase by Aureobasidium pullulans.