Abstract: Deepfakes pose significant threats to various fields, including politics, journalism, and entertainment. Although many defense methods against deepfakes have been proposed based on either passive detection or proactive defense, few have achieved both passive detection and proactive defense. To address this issue, we propose a Full-Defense Framework (FDF) based on ross-domain feature fusion and separable watermarks (SepMark) to achieve copyright protection and deepfake detection, combining the ideas of passive detection and proactive defense. The proactive defense module consists of one encoder and two separable decoders, where the encoder embeds one watermark into the protected face, and two decoders separately extract two watermarks with different robustness. The robust watermark can reliably trace the trusted marked face while the simi-robust watermark is sensitive to malicious distortions that make the watermark disappear after deepfake or watermark removal attack. The passive detection module fuses spatial and frequency domain features to further differentiate between deepfake content and watermark removal attacks in the absence of watermarks. The proposed cross-domain feature fusion involves substituting the “secondary” channels of spatial domain features with the “primary” channels of frequency-domain features. Subsequently, the “primary” channels of spatial domain features are used to replace the “secondary” channels of frequency-domain features. Extensive experiments demonstrate that our approach not only offers proactive defense mechanisms by using extracted watermarks, i.e. source tracing and copyright protection, but also achieves passive detection when there are no-watermarks, to further differentiate between deepfake content and watermark removal attacks, thereby offering a full-defense approach.