(E)-3,5-dihydroxy-4-isopropylstilbene is a new kind of anti-inflammatory drug for the treatment of anaphylactic disease such as psoriasis and eczema. The synthesis of (E)-3,5-dihydroxy-4-isopropylstilbene from (E)-3,5-dimethoxy-4-isopropylstilbene under microwave irradiation was investigated. Compared with the traditional heating method, microwave irradiation has the advantage that the demethylation reaction of (E)-3,5-dimethoxy-4-isopropylstilbene can be finished rapidly at relatively lower temperature with a higher yield and provides a new idea for the synthesis of stilbenes.