Vancouver-based Wylie Hui has started in the role.
He was CFO at Tintina Resources (CN:TAU) from 2010 to 2016 before starting his own firm.
UEX said in May, Ed Boney was "no longer CFO" without detailing how or why he left.
The explorer has several prospects in northern Saskatchewan, including the Christie Lake project.
A summer drill programme saw intercepts of over 20% U3O8.