NOVELTY - A polyaniline layered titanate nanocomposite material comprises polyaniline and protonized layered titanate, where titanium and oxygen form a two-dimensional layered structure with wrinkles by sharing sides and corners on the same octahedron. The polyaniline is located between layers of the protonized layered titanate; takes 7-8% of the total mass of the composite material; and is doped with hydrogen cation between layers of the protonized layered titanate. Thus, the polyaniline layered titanate is a type of nanocomposite material with micro p-n heterogeneous structure.    USE - A polyaniline layered titanate nanocomposite material is used for photocatalysis, a solar energy battery and a photoelectric sensor.    ADVANTAGE - The polyaniline layered titanate nanocomposite material can expand a photoelectric response range to a visible light region; and lowers a composite rate of light generated electron and light generated cavity.    DETAILED DESCRIPTION - A polyaniline layered titanate nanocomposite material having a chemical element of PANI/HxTi2-x/4()x/4O4.H2O, comprises polyaniline (PANI) and protonized layered titanate (HxTi2-x/4()x/4O4.H2O), where titanium and oxygen form a two-dimensional layered structure with wrinkles by sharing sides and corners on the same octahedron. The layer is 0.7-1.2 nm thick. The composite material has a certain amount of negative charges due to vacancy of titanium in the layers to have an n-type semiconductor property. The PANI is located between layers of the protonized layered titanate; takes 7-8% of the total mass of the composite material; is doped with hydrogen cation (H+) between layers of the protonized layered titanate, thus the composite material has a p-type semiconductor property. Thus, the polyaniline layered titanate (PANI/HxTi2-x/4()x/4O4.H2O) is a type of nanocomposite material with micro p-n heterogeneous structure.    x=0.65-0.75; and    ()=titanium vacancy in the layers.    An INDEPENDENT CLAIM is included for a method of preparing the polyaniline layered titanate nanocomposite material, comprising:    (A) preparing a layered cesium titanate by mixing and grinding cesium carbonate (Cs2CO3) and titanium dioxide (TiO2) at a mole ratio of 1:5.1-1:5.5, burning the mixture in a muffle furnace at 800-900 degrees C for 30-60 minutes, grinding the mixture after being cooled to indoor temperature and burning at 800-900 degrees C for 20-24 hours, and grinding the mixture again at 800-900 degrees C for 20-24 hours after it is cooled to indoor temperature to obtain the layered cesium titanate (CsxTi2-x/4()x/4O4);    (B) preparing the protonized layered titanate by mixing and stirring 1-1.5 moles/L hydrochloric acid (HCl) solution and layered cesium titanate solid for 3-4 days with a liquid solid ratio of 50-150 mL/g and replacing the 1-1.5 moles/L HCl solution once every 24 hours, washing and filtering the product with secondary distilled water until the pH value of the filtrate is 6-7 to obtain the protonized layered titanate, and putting the protonized layered titanate into a dryer containing a saturated sodium chloride (NaCl) solution for drying until constant weight;    (C) mixing the secondary distilled water and the protonized layered titanate solid according to the liquid solid ratio of 50-150 mL/g;    (D) applying an ultrasonic for 10-20 minutes to obtain a suspension;    (E) adding an aniline into the suspension according to the liquid solid ratio of aniline liquid to protonized layered titanate solid of 3.5-5.5 mL/g;    (F) stirring the suspension at 40-60 degrees C for 6-8 days until the suspension color is greenish black;    (G) washing and filtering the greenish black suspension at a sand core funnel with the secondary distilled water until the pH of the suspension is 6-7;    (H) then washing and filtering the suspension with ethanol until a characteristic absorption peak of aniline of the filtrate can be detected by a UV-visible light spectrophotometer; and    (I) drying the obtained sample in vacuum at 50-70 degrees C to obtain the polyaniline layered titanate.