BEIJING—China's exports and imports both rose sharply in May, while inflation slowed substantially, hopeful signs for the world's second-largest economy.

A raft of data released over the weekend by the Chinese government present a mixed picture, but overall suggest an economy stronger than many market players feared at the end of last week. A surprise-interest rate cut by the central bank Thursday prompted speculation that the monthly data for May would be especially weak.

Instead they showed that industrial-production growth ticked up slightly, albeit from an April pace that was the slowest in nearly three years, and that auto sales and property investment were stronger—signs of life for the Chinese economy, despite the sovereign debt crisis in Europe and a sluggish recovery in the U.S.

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Nelson Ching/Bloomberg News

A container ship berthed in Shanghai last month; China's exports and imports were both up sharply in May.

The data indicate that measures taken by the Chinese government to support growth are already having an effect, said HSBC economist Ma Xiaoping.

"It is almost certain that China's economy will bottom out in the second quarter and rebound in the third quarter," she added.

Government initiatives rolled out in recent weeks include purchase incentives for energy-efficient household appliances, targeted tax cuts and accelerated approval for investment projects by companies and local governments. On Friday, officials called for additional spending on railway construction.

Exports in May were up 15.3% from a year earlier, China's General Administration of Customs said on Sunday, beating April's feeble 4.9% and also well above the 6.9% rise forecast by a poll of economists. Similarly, May imports were up 12.7%, compared with April's 0.3% increase and expectations for a 3% rise.

Still, economists reacted cautiously to the strong trade data, warning against reading too much into one month's figures.

"The fact that it is stronger than expectations is relatively positive news, but that should be caveated by the fact that monthly trade data is very volatile from month-to-month," said IHS Global Insight economist Alistair Thornton.

On Saturday, the National Bureau of Statistics said that China's consumer price index for May showed the slowest rise since June of 2010. It was up 3% from a year earlier, easing from April's 3.4% pace and below expectations for a 3.2% rise.