Abstract: A method for preparing a lignin adhesive and a product thereof are provided. The method includes: treating a wood fiber raw material with a mixed solution; after the treatment, adding an organic solvent to perform a solid-liquid separation while stirring, subjecting an obtained liquid to a rotary evaporation to remove the organic solvent, and washing and drying the product to obtain the lignin adhesive. The method can remove a large amount of lignin from wood fiber raw materials at a low temperature, and in the process of lignin removal, the lignin adhesive is formed by the cross-linking reaction with the solvent in the system, realizing the separation of lignin and the formation of lignin adhesive simultaneously. And the method is simple, has low cost and high yield, and can realize the large-scale preparation of lignin adhesive and the efficient removal of lignin.