The 22-year-old arrived in London late on Thursday to undergo a medical with Harry Redknapp's side, who are currently bottom of the Premier League.
Yun was part of the South Korean team that won bronze at the London Olympics last year and is pushing for a regular place in the senior national side.
Since breaking into the Dragons first team in 2009, Yun made 86 appearances scoring four goals.
"We have agreed to transfer Yun to QPR, where Park Ji-sung plays," Chunnam said, adding that the deal would be completed after Yun passed a medical.
Terms of the deal were not disclosed.
Five points from safety in the English top flight, QPR have been keen to add to their squad in the January transfer window and have already signed French forward Loic Remy from Marseille.