The man suffered serious injuries while taking part in the Pirates of Skeleton Bay performance at the theme park in Windsor, Berks.
Families were said to have been left stunned as the performer fell.
Legoland confirmed the show has been closed until further notice.
“Hope the acrobat is ok.”
Paul Shannon, guest
A spokesman for the park said: ‘An incident involving one of the performers in our Pirate Stunt Show occurred at the LEGOLAND Windsor Resort today (Wednesday 26 July).
“Our first responders attended immediately and the individual concerned has been taken to hospital.
“The show is closed until further notice whilst an investigation takes place.
The Banshee rollercoaster opened in April 2014 in Ohio. The roller coaster features 4,124 feet of track making it the longest inverted roller coaster
Concerned witnesses offered their thoughts after the accident.
Paul Kelly tweeted: “We just witnessed an actor at Legoland Windsor having an accident during an acrobatic stunt. Hope he’s ok.”
Another said: “Thinking of the legoland pirate following a horrific accident. Get well soon buddy!…