China will cancel debts to the world's least developed nations.
Chinese President Xi Jinping has pledged to establish a $2bn (£1.3bn) fund to assist developing countries and to significantly increase investment.
Addressing a UN summit on development goals, Mr Xi said investment would reach $12bn over the next 15 years.
He also said China would cancel debts to the world's least developed nations, including small island nations.
Beijing, he added, would assist in 600 overseas projects in the next five years and offer more scholarships.
"Looking around the world, the peace and development remain the two major themes of the times," the Chinese leader said at the summit in New York.
"To solve various global challenges, including the recent refugee crisis in Europe, the fundamental solutions lie in seeking peace and realising development.
"Facing with various challenges and difficulties, we must keep hold of the key of the development. Only the development can eliminate the causes of the conflicts," Mr Xi said.
His pledges of aid give a big boost to the launch of the UN's new Global Goals for Sustainable Development - the day after all members states committed themselves to a hugely ambitious programme, the BBC's James Robbins in New York reports.
The plan aims to eradicate poverty and hunger by 2030.
It was China's extraordinary record shifting so many families out the ranks of the poor which ensured that the overall global record in poverty reduction under the previous Millennium Development Goals was substantial, our correspondent says.
But it was very patchy, he says, adding that now China is offering to help other countries - particularly in Africa - make the same transformation.