PEDV poses a significant threat to the global swine industry, necessitating rapid and accurate diagnostic methods for effective disease management. In this study, we developed a foldable, easy-to-use paper-based microfluidic analytical device (PAD) for on-site detection of PEDV. The device seamlessly integrates paper-based nucleic acid enrichment, LAMP reaction, and visual lateral flow detection into a single platform. Key parameters, including nucleic acid extraction protocols, chromatographic channel configurations, colorimetric indicators, and reaction temperature and duration, were systematically optimized. The resulting LAMP-PAD assay detects PEDV within 30 min at 60 °C, achieving a limit of detection of 4.82 × 10 copies/μL with no cross-reactivity against other viruses. When evaluated against RT-PCR using clinical specimens, the assay demonstrated a specificity of 100%, a sensitivity of 95.3%, and an overall concordance of 98.5%. This paper-based sensor offers a promising alternative for the rapid, on-site detection of PEDV and other highly transmissible pathogens.