Since late 2010, porcine epidemic diarrhea virus (PEDV) has rapidly disseminated all over the China and caused considerable morbidity and high mortality (up to 100%) in neonatal piglets. 79.66% (141 of 177) pig farms in 29 provinces (excluding Tibet and Hainan, China) and 72.27% (417 of 577) samples were positive for PEDV confirmed by reverse transcription-polymerase chain reaction (RT-PCR). The full-length S genes of representative field strains were sequenced. 33 field strains share 93.5%-99.9% homologies with each other at the nucleotide sequence level and 92.3%-99.8% homologies with each other at the amino acids sequence level. Most field strains have nucleotide deletion and insertion regions, and show lower homologies (93.5%-94.2%) with Chinese classical strain CH/S, however higher homologies (97.1%-99.3%) with recent strain CHGD-1. The phylogenetic analysis showed there are classical strains and variants prevailing in pig herd in China. PEDV has a high detection rate in pig herds in China. Sequence analysis indicated the S genes of recent field strains have heterogeneity and the variants are predominant.