To synthesize gastrodin via biotransformation of microorganism using p-hydroxybenzaldehyde as substrate.Using resting cell techniques with TLC and HPLC analysis, a strain of Rhizopus chinensis Staito AS3. 1165 which has the capability of biotransforming p-hydroxybenzaldehyde into gastrodin was screened from 50 strains of microorganisms. Preparative scale biotransformation was carried out under the optimal transforming condition. The product was obtained by chromatography, and characterized on the basis of its physical and spectral data.The product was identified as gastrodin on the basis of its 1H NMR, 13C NMR and EI-MS spectral data.The fact that gastrodin could be synthesized by microbial transformation implies a new approach to gastrodin production. As a result, this research will be of a great economic and social value.