Captain Of The Gate will chronicle the former prime minister's rise to power as he led Britain during the Second World War.
Spacey is currently starring as politician Frank Underwood in the hit US remake of BBC drama House Of Cards.
The Oscar-winning actor is now set to star as Churchill in the biopic, according to The Hollywood Reporter.
Ben Kaplan, whose previous credits include a TV movie for the History Channel about late US president Ronald Reagan, has written the screenplay. He has also worked on historical documentaries about Vietnam and the Second World War.
A director for the project has not been finalised.
Spacey, 54, is due to step down from his position as artistic director of The Old Vic in London next year, but will perform in a one-man show at the theatre which begins previews in May.
Churchill, who is widely regarded as one of the greatest leaders of the 20th century, was prime minister during the period 1940-45 and again from 1951 to 55.