Karyotype analysis is the study of chromosomes at mid-division, based on characteristics such as length of chromosomes, position of mitotic sites, ratio of long and short arms, presence or absence of follower, and with the help of modern technology, chromosomes are analyzed, compared, sorted and numbered, and diagnosed according to the variation of chromosome structure and number. Karyotype analysis can provide an important basis for cytogenetic classification, the relationship of relatives between species and the study of chromosome number and structural variation. It is divided into a bone marrow blood test and a peripheral blood test. Generally we are mainly due to the chromosomes of bone marrow, but there are individual patients whose chromosomes are not very well extracted, and for some hematological diseases with high white blood cells, we can also consider peripheral blood chromosome testing. The normal human karyotype is 46, XY is the normal male karyotype, female is 46, XX is the normal karyotype of chromosomes. Genetic disorders due to chromosomal abnormalities are studied for relatedness and also to explore species evolution.