Trade between North Korea and China stood at US$5.63 billion last year, up 284 percent from $1.98 billion in 2007, Seoul's unification ministry said in a report to the National Assembly.
North Korea's exports to China almost quadrupled to $2.46 billion in 2011, compared with $580 million in 2007, the data showed. Imports rose to $3.17 billion last year, from $1.39 billion in 2007.
The North's main export items were coal and iron ore, while primary imports from China were crude oil, gasoline and cargo trucks, it said.
North Korea, which has been under international sanctions over its nuclear and missile programs, has allowed Chinese firms to explore its mineral deposits.