Abstract: Since 2010， porcine epidemic diarrhea in newborn piglets seriously outbroke in most parts of China and caused huge economic losses to the pig industry. For the analysis of epidemic and genetic variation of porcine epidemic diarrhea virus (PEDV) in Zhejiang Province， PEDV in clinical samples collected during 2010-2013 was detected by RTPCR based on Nterminal of S gene， and fragments of 41 sequences were analyzed for variation of S1 gene. The results showed that the PEDV clinical detection rate increased from 4286% in 2010 to over 70% in 2013. The detection rate was significantly lower in July and August and was more than 50% across Zhejiang province. Sequencing analysis showed that the S gene of clinical detected strains were heterogenous with that of PEDV CV777， indicating that the current epidemic strain probably makes a new genotype and the mutation of PEDVS1 gene may be the reason for low immune protection of the existing CV777 strain vaccine．

Key words: porcine epidemic diarrhea, S1 gene, variant