High-temperature lithium, which is used as the neutron source in the International Fusion Material Irradiation Facility, reacts with oxygen, nitrogen, and moisture in the atmosphere. We estimated which lithium compounds might be stable under environmental conditions by using chemical equilibrium calculations, then performed austenitic stainless steel corrosion tests with the selected lithium compounds. The lithium compounds (reagents) and a steel specimen were heated to 1120K in an Al 2 O 3 Tammann crucible. After the test, the steel specimen was cleaned with alcohol and water and then weighed and metallurgically examined. We found that the steel was significantly corroded in Li 3 N, LiOH, and Li 2 O 2 environments. Because Li 2 O 2 is not stable according to the chemical equilibrium calculations, corrosion by Li 3 N and LiOH needs to be considered in high-temperature lithium applications.