The invention discloses an adaptive difference expansion-based reversible image watermarking method, which comprises a watermark embedding process, a watermark extraction process and an image recovery process; before watermarks are embedded, the original image needs to be pretreated, and the pretreatment comprises alternated division, difference calculation, image complexity calculation and parameter setting; in the embedding process, the corresponding watermarks are embedded by using adaptive expansion; additional information is embedded, and the watermark data and the additional information are mixed and embedded under a specific condition; in the extraction process, the additional information is first extracted, and the difference is calculated; the inverse operation of the adaptive difference expansion is performed, the watermark data are extracted, and the original difference is reduced; and finally, the image is reduced through the reduced difference. The method has reversibility, and can provide higher embedding capacity and better image quality, particularly under the condition of many embedded watermark data.