Abstract: The present invention provides a catalyst used in the production of PBS or its copolyesters and the preparation method thereof. The method comprises the following steps: (1) adding titanium alkoxide, silicon alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding complexing agent into the reaction system, then collecting catalyst from the products obtained in this step. Moreover, the method may comprises steps of: (1) adding titanium alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding silicon alkoxide and complexing agent into the reaction system, then collecting catalyst from the products obtained in this step.