The 63-year-old man was flying one of two planes which collided over Brighton Road, Shoreham, shortly before 4.30pm.
His plane crashed on Adur Recreation Ground. The other plane landed safely at Shoreham Airport.
Superintendent Neil Honnor said: “He has obviously found somewhere away from houses to land.
“There were people on the park at the time but they managed to get out of the way.
“It was tragic that pilot died but no one else was involved in the crash.”
The two men in the second plane were shaken but not seriously injured.
The pilot’s next-of-kin have been informed.