【Objective】 To analyze status of secondary prevention of prenatal birth defects in Qingdao city, in order to provide the basis for the prevention decision. 【Methods】 The three-level monitor network information of birth defects in Qingdao city were used, to analyze the monitor situation during pregnancy and the occurrence status of prenatal birth defects, in order to identify the impact of the secondary prevention on prenatal birth defects. The whole prenatal neonates were delivered in hospital from April 1 of 2009 to March 31 of 2010. 【Results】 The rate of prenatal birth defects was 60.34/10⁴. The top five defects diseases were congenital heart disease, total harelip, polydactyly, congenital hydrocephalus(tied for limb reduction defect), and syndactyly. The present situation of implementation about secondary prevention was that the prenatal screening rate of prenatal birth defects was 49.14%, the screening rate of ultrasound was 88.20%, the prenatal diagnosis rate was 58.37%, the prenatal detection rate was 63.95%. After therapeutic abortion, the incidence of prenatal birth defects decreased from 60.34/10⁴ to 43.89/10⁴(χ²=20.14,P<0.01). 【Conclusions】 Strengthening the work of health care in gestation period and raising the technology of prenatal diagnosis can reduce the birth defects effectively.