In the ultra high voltage（UHV）system

the non-uniform potential distribution of the dry-type air-core reactor will lead to corona discharge problems. Taking measures of using potential grading device

it can effectively improve electric field distribution and eliminate corona discharges. The analysis model is built in order to calculate and analyze the electric field distribution by finite element method of dry-type air-core reactor. The results show that it would be useful to solve problems in reactor design and could provide the reference to the research and development of UHV dry-type air-core reactor.