The plane is said to have fallen on open ground north of Heathfield just after 11 a.m.
Firefighters at a number of stations were scrambled minutes later and extinguished a blaze.
Firefighters confirmed they found a small plane that had crashed in a field when they arrived at the site.
Police and ambulance services are also currently on the scene.
The East Sussex Fire and Rescue Service said it could not yet release information on the injuries.
A Sussex Police spokesperson said: ‘Emergency services are responding to a light plane which has crashed at Herring Lane, north of Heathfield.
“The plane would have descended into the ground at 11:01 am on Tuesday August 4.
“There are no other details at the moment. “