To enhance the charge separation and transport efficiency of perylene diimide (PDI)-based organic polymer photocatalysts, three PDI-dominated polymeric photocatalysts (PDI-1, 5NDA, PDI-1, 4NDA and PDI-PDA) were synthesized via a facile polymerization method using 1,5-diaminonaphthalene, 1,4-diaminonaphthalene and p-phenylenediamine as linkers, respectively. The three PDI materials were characterized by FTIR, ¹³CNMR, XRD, XPS, UV-Vis, and photoluminescence spectrometer, evaluated for their photonic quantum efficiency, charge transfer resistance, and separation/transport efficiency of photogenerated carriers through photoelectrochemical experiments, and analyzed for their photocatalytic performance for H₂O₂ production in isopropanol aqueous solution under visible light. The results revealed that PDI-1, 5NDA and PDI-1, 4NDA crystallized in monoclinic systems but exhibited distinct unit cell parameters, while PDI-PDA adopted a triclinic crystal structure. All three materials demonstrated two-dimensional layered architectures and full-spectrum absorption within the visible light region, with PDI-1, 5NDA and PDI-1, 4NDA showing prominent absorption between 600~800 nm. PDI-PDA, PDI-1, 4NDA, and PDI-1, 5NDA were all typical n-type semiconductors, exhibiting photocurrent intensities of 3.0×10⁻⁷, 6.0×10⁻⁷ and 1.2×10⁻⁶ A, respectively, and corresponding photoelectrochemical impedances of 1.21×10⁶, 6.22×10⁵ and 4.23×10⁵ Ω, respectively, with PDI-1, 5NDA displaying the highest photogenerated charge carrier transport and separation efficiency. Under visible light irradiation, PDI-1, 5NDA achieved an exceptional H₂O₂ production rate of 113.485 μmol/(g·h), which was 1.3-fold and 2.2-fold those of PDI-1, 4NDA and PDI-PDA, respectively. This enhanced photocatalytic performance was attributed to the synergistic advantages of PDI-1, 5NDA's asymmetric structural features and extended π-conjugated system, which promoted the separation and transport of photogenerated carriers, thereby boosting H₂O₂ generation efficiency.