Abstract: The causes of birth defects include genetic factors,environment,food,drug,virus infection and others.Air pollution has been proved to be related to birth defects for a long time.There were enormous studies confirming that ambient air pollution is a risk factor for normal early development of fetus,including the study on adverse effects of thalidomide administration in 1960's and researches on the effects of ambient air pollutants on fetal development and on exchanges of nutrition and oxygen between the mother and the child during the present century.Recent studies also demonstrated that maternal exposure to air pollutants during pregnancy is associated with the occurrence of fetal cardiovascular diseases.The review summaries progresses in researches on relationships between birth defects and main ambient air pollutants such as sulfur dioxide,nitrogen dioxide,nitrides,and inhalable particulate matter.