"The Battle at Lake Changjin" has made $769 million since releasing in China on September 30.
In the state-funded movie, outgunned Chinese troops beat their US foes during a Korean War battle.
China's box office is the biggest in the world, meaning this film is also the biggest in the world.
A Chinese state-backed propaganda epic about the defeat of US troops is on track to become the country's highest grossing movie of all time.
"The Battle at Lake Changjin" follows a group of Chinese soldiers during the Korean War as they try to beat back US and allied forces from what is now China's border with North Korea, despite freezing conditions and staggering odds.
The film hit Chinese cinemas on September 30 - the day before China's weeklong National Day holiday - and has made $769 million to date, Variety reported, citing data from the consultancy Artisan Gateway.
The Chinese box office is the biggest in the world, meaning "The Battle at Lake Changjin" is the currently biggest film in the world.
It is also the most expensive movie ever made in China, costing more than $200 million, The Hollywood Reporter reported.
The film coincided with a concerted effort by Beijing to whip up nationalist sentiment on what is the 100th anniversary of the founding of the Chinese Communist Party.
And it appears to be paying off: Based on current trajectories, "The Battle at Lake Changjin" is set to become the highest grossing film of all time in the country, the state-run Global Times newspaper reported Sunday.
Currently, the most successful film ever to release in China is "Wolf Warriors II," which brought in $882 million in 2017. The star of the film, Wu Jing, also plays a prominent role in "The Battle at Lake Changjin."
However, it could be a closer call.
The Chinese ticketing portal Maoyan has estimated that "The Battle at Lake Changjin" will end up making a total $843 million, Deadline reported, which could make it narrowly lose out to "Wolf Warriors II." However, this would still mean it beats China's "Hi, Mom" to become the highest grossing movie of 2021 anywhere in the world.
At the Chinese box office, "The Battle at Lake Changjin" will soon be competing with the new James Bond film "No Time To Die," which premieres on October 29, and "Dune," which premieres on October 21.
The Chinese government has long maintained a tight grip over movie releases, often censoring or even banning certain movies seen to jeopardize its morals or its grip on power.