The using of the internet with its technologies and applications have been increased rapidly. So, protecting the text from illegal use is too needed . Text watermarking is used for this purpose. Arabic text has many characteristics such existing of diacritics , kashida (extension character) and points above or under its letters .Each of Arabic letters can take different shapes with different Unicode. These characteristics are utilized in the watermarking process. In this paper, several methods are discussed in the area of Arabic text watermarking with its advantages and disadvantages .Comparison of these methods is done in term of capacity, robustness and Imperceptibility.