Abstract: Objective To analyze the epidemic intensity and severity of hand,foot and mouth disease (HFMD) and changes of serotype of circulating pathogens in China during January-May 2017,and provide evidence for the early warning,prevention and control of HFMD epidemic.Methods The HFMD surveillance data were collected from National Notifiable Infectious Disease Reporting Information System for a descriptive epidemiologic analysis,the results were compared with the same period in 2016.Results During January-May 2017,the reported cases,severe cases and fatal cases of HFMD decreased by 40.7%,39.7% and 30.9% respectively compared with the same period in 2016,but the severe case rate,case fatality rate and death rate of severe cases were slightly higher.The incidence rate was highest in children aged 12-23 months (mild cases:7 940.4/1 000 000;severe cases:71.9/1 000 000).The mortality was highest in children aged 6-11 months (1.1/1 000 000).Compared with 2016,the reported cases,severe and fatal cases of HFMD decreased in most provinces,but severe cases and (or) fatal cases increased in Shandong,Shaanxi,Shanxi,Inner Mongolia and Fujian provinces.Virological surveillance indicated that enterovirus 71(EV71) and other enteroviruses were predominant pathogens,accounting for 41.4% and 41.6% respectively in laboratory-confirmed cases.In the mild cases,EV71 and other enteroviruses were predominant,accounting for 40.2% and 42.0% respectively.Severe and fatal cases were mostly caused by EV71(severe cases:61.9%,fatal cases:92.9%).The number of provinces where EV71 was predominant increased in 2017.Conclusion The HFMD epidemic level was lower in China during January-May in 2017 compared with the same period in 2016,but the disease severity increased slightly.The increase of severe and fatal cases in some provinces was probably due to the increased proportion of EV71 infection,shift of predominant enterovirus serotype and susceptible population accumulation.The EV71 vaccine immunization should be promoted to reduce the incidence of the severe and fatal cases.Provinces where other enteroviruses were predominant,especiallythe province with high proportion of other enteroviruses in severe cases,should enhance the serotype identification of other enteroviruses.