Deacidification and self-cleaning are important for the preservation of paper documents. In this study, nano-CaCO₃ was used as a deacidification agent and stabilized by nanocellulose (CNC) and hydroxypropyl methylcellulose (HPMC) to form a uniform dispersion. Followed by polydimethylsiloxane (PDMS) treatment and chemical vapor deposition (CVD) of methyltrimethoxysilane (MTMS), a hydrophobic coating was constructed for self-cleaning purposes. The pH value of the treated paper was approximately 8.20, and the static contact angle was as high as 152.29°. Compared to the untreated paper, the tensile strength of the treated paper increased by 12.6%. This treatment method endows the paper with a good deacidification effect and self-cleaning property, which are beneficial for its long-term preservation.