US president discusses trade with Wen Jiabao before travelling to Seoul.
US politicians and industry groups have said that Beijing is holding its currency at such a low level against the dollar that it is widening the trade gap between China and the US.
After his talks with Wen, Obama wrapped up his trip to China by visiting the Great Wall, before he left for South Korea.
The US president is expected to focus on the issue of North Korea's nuclear weapons programme during a meeting with Lee Myung-bak, South Korea's president, on Thursday.
Hu Jintao, China's president, and Obama promised on Tuesday to hold joint efforts on the economy, climate change and North Korea but few concrete agreements emerged from the talks.
Both sides spoke about building a "positive, co-operative, and comprehensive" relationship but steered clear of making any solid commitments, Melissa Chan, Al Jazeera's correspondent in Beijing, said.