Spontaneous abortion is a complication of pregnancy that terminates before 28 weeks of gestations. The incidence is about 15 % ~ 40 %. In recent years the assisted reproductive technology(ART) is also facing the problem of high incidence of spontaneous abortion. Etiology of spontaneous abortion is very complex. Besides genetic factors,there are anatomical factors,endocrinological factors,infection factors,environmental factors,immunological factors,prethrombotic state and maternal systemic diseases and so on. Cytogenetic studies of spontaneous abortion are mainly in two aspects,one is embryonic chromosomal abnormalities,including the number of chromosome abnormalities and abnormal structure；the second is couple of chromosome abnormalities. In spontaneous abortion the embryonic chromosomal abnormal detection rate is around 60 % and this ratio declines with the increase in the number of abortions. Most of the number of embryos abnormalities are trisomy,triploids and X monomer. Less structural chromosomal abnormalities of embryo include chromosomal breakage,inversions,deletions and translocations and so on. In couples with spontaneous abortion,especially recurrent spontaneous abortion couples,the abnormal chromosome detection rate is around 8 %. With the number of abortion increases,this proportion increases too. The most common abnormality of chromosome of adult is balanced translocation. Nowadays there are great developments in cytogenetic detection technology. From the traditional chromosome karyotype analysis and fluorescence in situ hybridization techniques (FISH) to chromosomal microarray chip analysis and the second generation sequencing technology,we can make further research of cytogenetic of spontaneous abortion. These researches have a very important significance in the area of etiology of spontaneous abortion and do great help to guide the couples confused by recurrent spontaneous abortion in their next childbirth.