The latest signs of weakness have prompted calls for still more stimulus measures. Beijing has cut interest rates twice since the start of June and is pumping money into the economy through higher spending on building low-cost housing and other public works.
Economic growth fell to a three-year low of 7.6 percent in the quarter ending in June. The International Monetary Fund and private sector analysts have trimmed their forecasts for the year but say growth should be about 8 percent above the official 7.5 percent target but below the double-digit rates of recent years.
The slowdown is politically dangerous for the Communist Party because it raises the risk of job losses and unrest at a time when the ruling party is trying to enforce calm ahead of a handover of power this year to younger leaders. Export industries employ millions of workers and weak sales, coupled with higher costs, have led to a wave of bankruptcies.
China's trade growth has fallen steadily this year as global demand for its exports cooled and efforts to boost domestic consumption have failed to gain traction as fast as the government hoped.
In July, its global trade surplus narrowed by 20.3 percent from July 2011 to $25.1 billion but was this year's second biggest after June's $31.7 billion.
Exports were $176.9 billion while imports were $151.8 billion.
The trade surplus with the 27-nation European Union, China's biggest trading partner, narrowed by 37.9 percent to $10.8 billion, reflecting sluggish European demand due to the continent's debt crisis. The surplus with the United States narrowed by 4.8 percent to $19.9 billion.
Beijing has set a goal of increasing total trade by 10 percent this year, a target that looks increasingly hard to meet. Trade grew 9.2 percent for the first half of the year but the rate fell to 7.1 percent for the first seven months.