By Agence France-Presse
The figures were released hours after President Donald Trump threatened to slap tariffs on the totality of Chinese goods imported into the United States, worth half a trillion dollars.
The world's two biggest economies have been locked in a months-long trade dispute, with negotiations going nowhere and fears that it could damage the global economy.
Trump imposed customs duties of up to 25 percent on $34 billion worth of Chinese goods in July, and on another $16 billion in August, triggering swift tit-for-tat responses from Beijing.
But the tariffs do not appear to have dented the appetite for Chinese-made products in the United States.
Chinese exports to the United States rose to $44.4 billion in August, a 13.2 percent increase from the same period last year, according to customs data. Imports from the United States reached $13.3 billion, a two percent increase from the previous year.
China's trade surplus with the United States reached $31 billion in August, an 18.7 percent increase from the same month last year and up from its previous record, $28.9 billion, in June this year, according to customs data.
While China's trade surplus with the United States grew again, it remained stable with the rest of the world at $27.9 billion in August.
Global exports increased by 9.8 percent while its imports rose by 20 percent compared to the same month last year, according to customs data.
The figures were well below July's performance, when exports had jumped 12.2 percent and imports grew 27 percent.
Trump has boasted that trade wars are "easy to win" and warned he would hit virtually all Chinese imports if Beijing does not back down and take steps to reduce its $335 billion surplus with the US.
He said Friday that tariffs on another $200 billion in Chinese goods are "in the hopper" and "could take place very soon".
Beijing has warned that it would hit back with duties on $60 billion in American products -- a much smaller figure that shows China will not be able to match US tariffs dollar-for-dollar.
But businesses warn there are other ways China can strike back, through regulations and other administrative means, or even through sales of its large holdings of US Treasury debt.
Trump told reporters traveling with him to Fargo, North Dakota that "behind that, there's another $267 billion ready to go on short notice if I want."
That would cover virtually all the goods imported from the world's second largest economy.
"That totally changes the equation," Trump said.
White House economic adviser Larry Kudlow just hours before said talks with Beijing were continuing to try to defuse the conflict, and that he was hopeful that a solution could be found.
The last effort at a negotiated solution came in late August with meetings between low-level officials, but nothing came of it.
In Beijing, China's Commerce Ministry said Thursday it was ready to retaliate.
"If the US dogmatically implements any new tariff measures against China, China will have to take the necessary countermeasures," commerce spokesman Gao Feng told reporters.