Speaking at a rally in Colorado Springs, he also criticized Brad Pitt, winner of the best supporting actor gong for Once Upon a Time in Hollywood, calling him a "a little wiseguy".
An energetic Mr Trump asked supporters: "By the way, how bad were the Academy Awards this year? Did you see them?"
Imitating an announcer, he said: "And the winner is ... a movie from South Korea. What the hell was that all about? We've got enough problems with South Korea with trade. On top of that they give them the best movie of the year? Was it good? I don't know."
The president revealed his own taste in films, asking why a film like Gone with the Wind or Sunset Boulevard couldn't win.
"You know I'm looking for, like, where .... Let's get Gone with the Wind? Can we get, like, Gone with the Wind back please? Sunset Boulevard ... so many great movies.
"The winner is ... from South Korea. I thought it was best foreign film, right? Best foreign movie! No, it was the ... did this ever happen before?"
Neon, Parasite's US distributor, hit back at the president's criticism of the subtitled film, tweeting: "Understandable, he can't read."
Gone with the Wind, released in 1939, won eight Academy Awards, including one for Hattie McDaniel, the first African-American to win an Oscar. However, the film's sympathetic portrayal of Confederates during the civil war has been criticized since.
— NEON (@neonrated)February 21, 2020
Sunset Boulevard, released in 1950, is a more surprising choice of film for the usually conservative-minded president – a dark drama narrated by a dead man, it tells of an ambitious young screenwriter who gets ahead by having an affair with an ageing former silent era movie star. In mood it is not dissimilar to the twisty thriller Parasite.
The president hit out at Pitt, who made a point about Mr Trump's impeachment trial during his Oscar acceptance speech.
Referring to Republican senators refusing to hear potentially explosive evidence from former national security adviser John Bolton, Pitt said: "They told me I only have 45 seconds up here ... which is 45 seconds more than the Senate gave John Bolton this week."
Mr Trump told the rally: "And then you've got Brad Pitt – I was never a big fan of his. He got up with his little wiseguy statement. Little wiseguy! He's a little wiseguy."