Porcine epidemic diarrhea (PED) causes significant economic losses to the pig farming industry worldwide and currently lacks an effective vaccine. Multiple detection assays and protein purification methods use magnetic nanoparticles due to their biocompatibility, high specific surface area, and solution suspension properties. In this study, a two-probe competitive ELISA based on magnetic nanoparticles for detecting PEDV N protein was developed. MNPs-N and McAb-HRP probes were prepared and the procedure was optimized to identify the ideal reaction conditions. Compared to other methods, the developed method shortens the detection time to 50 min. The coefficient of variation (CV) for intra- and inter-lot replicates was less than 10 %, with reproducibility. The coincidence rate with commercial kits is 93.07 %, making this method reliable and suitable for PED immune monitoring and diagnostics.