The invention discloses a method for chemically synthesising gastrodin, comprising the following steps of: in the presence of a molecular sieve, under the catalysis of Lewis acid, and performing glycosylation reaction on pent-acetyl-b-D-glucose and p-cresol in an organic solvent with to generate 4-methylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside; then preparing 4-halomethylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside from 4-methylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside and N-halosuccinimide in the presence of an initiator, and then reacting 4-halomethylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside with the mixed solution of glacial acetic acid and tertiary amine to obtain 4-acetoxylmethylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside; and finally removing the acetyl protecting group from the 4-acetoxylmethylphenyl-2,3,4,6-O-tetra-acetyl-b-D-glucopyranoside in an alkaline condition to obtain gastrodin. Compared with the traditional method, the method disclosed by the invention has easily available raw materials, and is short in reaction time, capable of preparing the reaction product in each step via recrystallization, simple, and more suitable for industrialized production for gastrodin.