Hybrid film based on layered double hydroxides (LDHs) and acidified carbon nanotubes (aCNTs) was synthesized by constant pH coprecipitation method and was used as the novel nanofiller for poly(vinyl alcohol) (PVA) films. The obtained LDH-aCNTs hybrid materials were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The microstructure and mechanical properties of the PVA/LDH-aCNTs hybrid film were investigated. The mechanical tests suggested that the tensile strength of the PVA hybrid film containing 3 wt % LDH-aCNTs reached a maximum value. Compared to pure PVA, the tensile strength of PVA hybrid film was increased by 41%. The compatibility between aCNTs and PVA was effectively improved by LDHs, which enhanced the mechanical properties of the film. The water absorbency test showed that the water absorption of 5 wt % PVA/LDH-aCNTs hybrid film declined by 58% compared with the pure PVA (water absorption rate being 649%). The hydrogen bonding formed between oxygenic functional groups on the LDH-aCNTs hybrid nanoparticles and hydroxyl in the chain of PVA, which reduced the bare hydrophilic group and declined the water absorption. The mechanical properties and water resistance of the PVA/LDH-aCNTs hybrid film were also improved, which could hopefully broaden its application domain.