To improve the tampering detection performance and the security of Word document watermarking method,a fragile Word document watermarking scheme based on critic al-character double verifications is proposed.In this method,all characters in the Word document are divided into the critical characters and non-critical ones.The 8bits watermar k data generated by each character are embedded into the special properties of the same character for the purpose of resisting g eneral tampering.In order to improve the tampering detection performance for the critical chracters.the 8bits watermark data generated by the critical characte r act as the second watermark data,which are embedded into the special propertie s of the other non-critical chracter so as to resist collage-attack.When this solution,it can realize the double verifications of the critical character.In ad dition,we also discuss the impact of watermark data embedded into the special pr operties of the character on th e size of Word document by statistical experiments.All those experimental result s show that the watermark data embedded into the special properties can improve the security of the watermarked Word document,and the dual watermark data which are embedded into the critical chracter can improve the tampering detection perf ormance greatly.