Abstract: Electromagnetic method is one of most important methods of isotope separation. From the early 1960's to the mid 1980's, four electromagnetic isotope separators have been developed and constructed at the China Institute of Atomic Energy. For almost 25 years, CIAE has been separating more than 100 isotopes of 20 elements. The enriched isotopes produced in our Institute have been supplied to more than 100 different organizations in our country and to a few foreign countries.