Abstract: Microsatellite DNA is the main part of repeat sequence in eukaryotic genome. Ubiquitous distribution, high polymorphism, low spontaneous mutation and easy for detection, all these characters make it an ideal genetic marker for gene localization, gene maping, population study, individual identification, etc. Besides, it also closely correlates with some tumors and genetic disorders. In radiation field, microsatellite DNA has also been widely used in detecting ionizing radiation induced mutagenesis, teratogenesis and carcinogenesis.