It is the third serious mishap in two months at the site where the blockbuster is being made.
A spokeswoman for film giant Universal said: “We had an injury on the set of Fast 9 with one of our stuntmen.
“We have halted production for the day to focus on this situation.”
The victim, who has serious head injuries, was airlifted to hospital from the Warner Bros Studios in Leavesden, Herts, just before midday on Monday.
Hertfordshire police said: “Officers are on scene to assist and carry out initial inquiries.”
East of England Ambulance Service said: “An ambulance, three officer vehicles and Essex and Herts Air Ambulance were called to Leavesden.
“One patient with a serious head injury was transported by air ambulance to the Royal London Hospital.”
On July 11, fire crews tackled a blaze for 15 hours at the site.
While in June, a man was stabbed in the neck on the set of an adaptation of Roald Dahl’s The Witches being filmed there.
At Pinewood Studios, in nearby Buckinghamshire, an explosion on set of the forthcoming Bond 25 movie injured a crew member on June 4.
Fast and the Furious 9, starring Vin Diesel and Michelle Rodriguez, is due to be released next year. It is not yet known if the accident will affect the release date.
As well as the Fast and the Furious franchise, all the Harry Potter films have been filmed at Leavesden along with Mission: Impossible. James Bond was also filmed there in the past.
Fast and Furious lead actor Paul Walker was killed in a car crash in 2013 while away from filming.