Regarding climate change, China will work hard to realize its targets for controlling greenhouse gas emissions regardless of difficulty, Wen said.
China will work with the EU and negotiate on the basis of "common but differentiated responsibilities," Wen added.
China is dedicated to safeguarding the international nuclear non-proliferation system and the peace and stability of the Middle East, he said.
China will keep communicating with parties involved in the Iranian nuclear issue in a responsible and constructive manner to bring an early resolution to the issue, he added.
Barroso is paying an official visit to China. He will attend the opening ceremony of the Shanghai World Expo after his time in Beijing.