This study focuses on investigating how the PED (Porcine Epidemic Diarrhea) virus influenced the production efficiency of swine industry in Taiwan. A total 96 valid sample data were collected during March of 2014. The Data Envelopment Analysis (DEA) was adopted to evaluate production efficiency before, and after, the PED events. Results show that the PED events in Taiwan had weakened overall technical efficiency (TE) about 8.6%. Large scale farms, older farms, and Central area appeared to be the most heavily impacted. Meanwhile, the reproductive rate of Taiwanese hog farms was found to exhibit a polarization in that some farms were producing at a high efficiency, while others were not. Lastly, the percentage change in production efficiency in the DEA estimation are very close to the percentage changes in inventory on farms reported by government. This may imply that the DEA can be further discussed regarding the capability of estimation.