Abstract：With the development of the technology of computer and Internet, the distributing and copy of digital watermark become widely dispersed. Copyright protection also becomes outstanding .The digital watermark is a kind of copyright protection technique which appears in recent years, it overcome the traditional password to learn to keep secret the product after decrypt no longer safe blemish. Understand the history and the research present conditions of the digital watermark, the different between it and traditional cryptology, and the relation of them.

In this article , study the tool of MATLAB, make an experiment on embedding the watermark into picture ,carry out a arithmetic which embedding of watermarking . The result prove the MATLAB is efficiently and conveniently .Introduced embedding and detecting of arithmetic that based on content and format :changing the size and color of some words is basis of feature coding idea and format of the word, Study and understand the embedding、build 、detecting of watermarking , good robustness in counteracting traditional attacks．

Keywords：Watermarking,，MATLAB，digital watermarking of text,，Robustness，color