It was the third consecutive month of gains, with August showing a surplus of $28.69 billion and July $25.28 billion, the General Administration of Customs said.

"The surplus jumped mainly because imports posted a much bigger slow down than exports as commodities prices and shipping rates slumped," said Li Jian, a Ministry of Commerce analyst, Xinhua news agency reported.

September exports totaled $136.4 billion, up 21.5 percent from last year. Imports during the month totaled $107.1 billion, up 21.3 percent from last year. The percentage increase in imports year-on-year, however, was lower than 23.1 percent for August and 33.7 percent for July.

The September surplus was also helped by a slower increase in the value of the Chinese yuan against the U.S. dollar.

Going forward, there is concern in China that slowing global demand may affect exports.

China's trade surplus in the first nine months of this year totaled $180.9 billion, down $4.92 billion -- 2.6 percent -- from the same period last year.