Abstract: Response surface analysis was used to get the optimal conditions for production of pinoresinol diglucoside (PDG) by a strain of Phoma sp. (SP-16F) in liquid cultivation. Initial pH value, rotation speed and media volume were investigated. A model showed good agreement with the experimental data of PDG production and cultivation conditions. By solving the model, the optimal conditions for PDG production were obtained at initial pH 8.37, rotation speed 193 r/min, volume of medium 100 mL, inoculation volume 10%, and temperature 28℃. Under the optimal conditions, the PDG production reached 30 mg/L. The variation between the practical data and predicted data was less than 5%.