Abstract: In order to improve the yield of alpha- pinene,optimization of the fermentation medium for strain YJM28 was carried out by response surface analysis.The optimal carbon and nitrogen source for YJM28 were glucose and peptone,respectively.Three most important substrates for YJM28 were screened via Plackett- Burman experiments and using Design- Expert software. Optimal concentrations of the three substrates were confirmed by Central-Composed design and response surface analysis.The results were 63.78μL /100 m L of trace element solution,2.77 g / L of glucose and 9g / L of peptone. Fermented with the optimized medium,the yield of alpha- pinene after 48 h reached 33.26 mg / L,increased by 6.75- fold compared with the original medium.