The country's trade surplus with the U.S. grew to $31 billion last month from $28.09 billion in July, as its total trade surplus narrowed, General Administration of Customs data showed Saturday.
The value of the Chinese yuan has dropped as the trade war with the United States has escalated.
"In the short term, it is difficult for the trade gap to narrow because American buyers cannot easily find alternatives to Chinese products," Bank of Communications Economist Liu Xuezhi told the Wall Street Journal.
The yuan sunk nearly 9 percent against the U.S. dollar from April through July, according to China's Wind Information data. The currency value didn't change much in August as China's central bank intervened to prevent more depreciation.
Still, it has been cheaper for U.S. consumers to buy Chinese goods with the weaker yuan.
China's exports to the United States rose 13.2 percent in August from a year earlier, accelerating from an 11.2 percent increase in July, the Journal reported based on its calculations from customs data.
Trump said Friday he would slap another $267 billion in tariffs on Chinese goods in a third round of tariffs. This is on top of a second round of tariffs on $200 billion in Chinese goods the Trump administration is preparing, and $50 billion in tariffs that have already been imposed.
The new $267 billion in tariffs would cover the value of all goods the Unites States buys from China, U.S. government data from last year show.
The United States imported $505 billion in Chinese products last year, according to U.S. Census Bureau data.