China's trade surplus has narrowed to a disappointing $US15.2 billion ($16.12 billion) in September from $US28.6 billion in August, customs figures show.
Exports fell 0.3 per cent year-on-year to $US185.64 billion last month, while imports increased 7.4 per cent to $US170.44 billion, the figures said on Saturday.
The September trade result was worse than expected with a survey of analysts forecasting a trade surplus of $US27 billion.
China's trade performance is a key element of the country's economic growth figures, the latest of which for the third quarter through September are due for release next Friday.
A string of strong data in recent months, including for exports and industrial output, have suggested quarterly growth may accelerate, spurring optimism following a surprise downturn during the first half of the year.
For the first nine months of the year, customs said that exports increased 8 per cent to $US1.61 trillion, while imports increased 7.3 per cent to $US1.45 trillion.
The trade surplus for the period stood at $US169.4 billion, up 14.4 per cent, the figures showed.
China is coming off its worst annual economic performance since 1999.