China's economy showed a sign of recovery currently, but was still in a crucial phase and faced uncertainties both from home and abroad, said Yao jingyuan, Chief Economist with the National Bureau of Statistics on Sunday.

Yao made the remarks in an exclusive interview with Xinhua, saying the government should make down-to-earth efforts to implement the bouquet of economic stimulus measures in the second half to concrete the recovery momentum.

China, the world biggest development country, saw its economy growth slowed down amid the world financial crisis. However, boosted by the government's 4-trillion yuan ($586 billion) stimulus package, its GDP grew 7.9 percent in the second quarter after sinking to 6.1 percent in the first three months.

"Although the country's economy began to rebound recently, the economy is not on a solid footing and faces uncertainties both from home and abroad," he said.

A crucial external environment was and would still be the main challenge of China's economy, according to Yao. A shortage of orders from overseas markets put Chinese companies in great difficulties.

During the first half this year, China's exports totaled $521.53 billion, representing a decrease of 21.8 percent over the same period last year. Imports was $424.59 billion in the first six months, down 25.4 percent year-on-year.

Trade surplus stood at $96.94 billion in the first half, down $1.3 billion or 1.3 percent over the same period last year.

"We should pay enough attention to the difficulties and get fully prepared for that," Yao said. "Efforts should also go to economic structure adjustment."

To further lift the country's economy, Chinese President Hu Jintao and Premier Wen Jiabao on July 23 called for efforts to stick to the government's proactive fiscal policy and moderately easy monetary policy to sustain the economic growth.