The invention discloses a tetrahydro benzothiophene derivative and the application thereof to the preparation of a glycogen synthase kinase 3 beta inhibitor. The tetrahydro benzothiophene derivative, pharmaceutically acceptable salt, optical active body or racemate thereof has a chemical structure as shown in a formula I. Experiments show that the compound has good GSK-3 beta inhibitory activity. In addition, the invention further provides a method for preparing a tetrahydro benzothiophene compound. The method is short in synthesis route, simple in preparation process and easy to operate, and can meet the requirements of large-scale industrial production.