A novel method of natural language information hiding is presented based on Chinese mathematical expression. The method can convert Chinese text into bit string by using the thought of Chinese mathematical expression, and then embed the secret message into the text by utilizing the replacement of synonyms, variant forms of the same word, the adding or deleting of the empty words, and the shift conversion of the sentence. Experimental results show that the method can achieve a faster conversion of the text into the binary string, a better degree of information-carrying capacity and a better result with the imperceptibility.