The invention discloses a method for preparing sustained-release composite volatile rust preventive paper. The method comprises the following steps: an anti-rust agent (benzotriazole) is loaded onto nanosized zeolite powder through a negative-pressure impregnation method, then spray drying is performed to coat the surface of the nanosized zeolite powder with chitosan to obtain a chitosan-modified zeolite compound, after that, graft copolymerization is performed on the chitosan-modified zeolite compound and acrylamide to obtain a chitosan-modified zeolite-polyacrylamide composite sol, the chitosan-modified zeolite-polyacrylamide composite sol is added into paper pulp, and papermaking is performed to obtain the sustained-release composite volatile rust preventive paper. According to the method, on the one hand, the sustained-release purpose of the anti-rust agent is achieved through multi-layer coating treatment, and the anti-rust effect is lasting, and on the other hand, the anti-rust agent and paper fibers are firmly combined to guarantee stable anti-rust performance.