The State Security Court upheld the man's conviction on charges of "sharing intelligence with Iran, importing electricity generators and devices used in the Iranian nuclear programme from the United Kingdom and attempting to illegally re-export these devices to Iran," the official WAM news agency reported.
The man, whose identity has not been disclosed, was found guilty by a lower court in April and sentenced to 10 years in jail to be followed by deportation.
But the UAE and other Sunni-ruled Gulf Arab states remain deeply opposed to the influence of Shiite-dominated Iran in the Middle East.