OBJECTIVE： To optimize the conditions of extractive microbial transformation for producing L-phenylacetylcarbinol （L-PAC）. METHODS： HPLC was used to determine the concentration of L-PAC， which was extracted by saccharmyces cerevisiae. Using L-PAC concentration as response value， Box-Behnken response surface design was adopted to investigate the 3 main factors of benzaldehyde， Triton X-100 and glucose dose， and verification test was conducted. RESULTS： The interaction between benzaldehyde and Triton X-100 was the most significant. The optimized combination was as follows as benzaldehyde of 1.1％， Triton X-100 of 0.14 g/mL， glucose of 0.028 g/mL. The average concentration in verification test of L-PAC was 28.04 mmol/L （RSD＝1.35％， n＝3）， showing 0.11％ relative error with the predicted value of 28.01 mmol/L. CONCLUSIONS： Response surface method has optimized the conditions of extractive microbial transformation for producing L-PAC， obtained optimal combination of each factor， and provided favorable reference for volume-producing L-PAC.