Police spokesman Albin Naverberg says crew onboard handcuffed the man during the flight on Sunday and handed him over to police when the plane landed in Stockholm.
Henrik Kelfve, spokesman for airport operator Swedavia, says the man tried to enter the cockpit on the Emirates' flight.
Naverberg says police detained him on suspicion of preparing aircraft sabotage after interviewing the plane's crew.
Swedish tabloid Expressen reported the man had been running through the plane, screaming he had a bomb, about an hour after the departure from Dubai. Naverberg said police had no details of any explosives and declined to comment further.