Objective To analyze the dynamic changes of perinatal defects in Lishui city from 2005 to 2014.Methods According to hospital-based data,87 294 fetuses and infants aged from 28 weeks of gestation to 7 days after birth were monitored for birth defects in Lishui city from 2005 to 2014.Results Among 87 294 perinatal infants,birth defects were found in 1 914 cases with a incidence of birth defects of 219.3/ten thousand,which was on the rise year by year except 2009.The incidence of birth defects was 235.1/ten thousand (737/31 352) in urban areas,which was significantly higher than that in rural areas (210.4/ten thousand,1 177/55 942) (x2 =5.705,P ＜ 0.05).The incidence of birth defects of boys and girls was 221.1/ten thousand (1 005/45 453) and 212.8/ten thousand (890/41 822),respectively (x2 =0.707,P ＞ 0.05).Among 1 914 cases of defects,657 were detected prenatally and 1 257 case were detected within 7 days after birth.Congenital heart disease was the most common birth defect,followed by polydactyly,cleft lip,microtia and syndactyly.Birth defect accounted for 32.74％ (278/849) of all perinatal deaths and the ratio was on the rise since 2010.Conclusion There is an upward trend in incidence of birth defects in Lishui city in the last decade;the incidence of birth defects in urban areas is significantly higher than that in rural areas;the incidence of congenital heart disease is high,and birth defects are the main cause of perinatal death.