Avatar is on course to become the highest grossing film of all time, making $US1.14 billion since its release.
The Hollywood Reporter said James Cameron's film had overtaken the $US1.12 billion taken by The Lord of the Rings: The Return of the King.
But Cameron still has a way to go to top Titanic's $US1.84 billion.
However, the BBC reports Avatar's huge box office takings could be partly due to the higher cost of 3D film tickets.
Titanic, which won the best director Oscar for Cameron, made a new box office record during its release from 1997-1998.
Earlier this month, Avatar became the fastest movie ever to achieve $US1 billion in ticket sales around the world.
Distributors 20th Century Fox said it had earned more than $US350 million in the United States and more than $US670 million in the rest of the world since 17 December.
The sci-fi epic, about a disabled marine who infiltrates a race of giant blue aliens, mixes live action with digitally-created performances. Its budget was at least $US300 million.