Embodiments of the present application provide a blockchain-based data evidence storage method, a blockchain-based data check method, and relevant apparatuses. The data evidence storage method comprises: performing irreversible encryption on data content of a target file to obtain irreversibly encrypted data of the target file; storing the irreversibly encrypted data in a blockchain and obtaining on-chain evidence storage information of the irreversibly encrypted data; generating a digital watermark of the on-chain evidence storage information; embedding the digital watermark into the target file; and storing the target file embedded with the digital watermark of the on-chain evidence storage information.