The meeting will be attended by United Nations Secretary General Antonio Guterres, World Bank President Jim Yong Kim and heads of 29 countries.
The two-day meeting included President Vladimir Putin of Russian Federation and Turkey's President Recep Tayyip Erdogan, along with the presidents or prime ministers of Italy, Hungary and Greece, as well as most of China's Asian neighbors.
In a major setback to China, Europian Union has decided not to issue an official statement on its "modern Silk Road" project, said a report.
India skipped the Belt and Road Forum (BRF) due to its sovereignty concerns over the $50 billion China-Pakistan Economic Corridor, which passes through Azad and Jammu Kashmir.
President Xi Jinping's state visit to Cambodia past year helped develop the two countries' friendship under the new global politics and economic status, Li said.
It set the tone for the two-day forum that started on Sunday to discuss the Belt and Road plan, which aims to connect China with Europe, Asia and Africa through infrastructure and investment.
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Xi stated today during the closing speech of the summit that the leaders supported closer coordination in economic policy and a more powerful synergy of their development strategies, in an effort to achieve systematic and interconnected progress.
On Saturday, Pakistan and China inked new deals worth almost Dollars 500 million, covering airport, port and highway construction, it said. He urged Xi called for governments to pursue "greater openness and cooperation" and "reject protectionism".
Xi also pledged an additional assistance worth 60 billion yuan ($9.5 billion) for developing countries and global organisations participating in the initiative to improve people's well-being over the next three years.
China is promoting itself as a champion of free trade in response to pressure in the USA and Europe for restrictions on imports.
In contrast, Xi said China's Belt and Road plan would be inclusive and open to all. "This concept showed that the leadership of China - President Xi and his team - believed in not just growing China but also growing other countries in the region and in the world", he said.
The premier also proposed enhancing defence and law-enforcement cooperation and strengthening exchanges in areas including education, tourism, protection of historical relics, medicine and health.