This paepr presents a secure transmission system for document image using mixing algorithm. For this, we apply DM and RDM algorithm propoposed before. The transmitter embeds secretly the signature onto secure document, embeds it to non-secure document and transfers it to the receiver. The receiver makes a check of any forgery on the signature and the document. The total amount of data transmitted and the image quallity are about the same to that of the original document. Thus, a third party can not notice the fact that signatures and secure document is embedded on the document.