"This is the economic initiative and it deals with the economic cooperation, so we do not want it to be politicized", Wang said at a briefing answering the question, whether some Western leaders did not confirm their participation due to lack of understanding of the initiative.
Since 2013, China has invested more than 50 billion USA dollars in Belt and Road countries.
According to Wang, 28 heads of state and government leaders will attend the forum.
The summit, scheduled to be held on May 14 and 15 in Beijing, will be China's major diplomatic event this year as it pushes ahead with President Xi Jinping's flagship "One Belt, One Road" programme to launch a series of infrastructure projects across Asia, Europe and Africa.
Chinese companies' investment in countries along the Belt and Road rose again in Q1.
Chinese President Xi Jinping will attend the opening ceremony of the Belt and Road Forum for International Cooperation in May, Chinese Foreign Minister Wang Yi said on Tuesday.
Aside from Putin, other Chinese allies including Pakistani President Nawaz Sharif and Myanmar's Aung San Suu Kyi will attend, as will Philippine President Rodrigo Duterte, Indonesian President Joko Widodo and Italian Prime Minister Paolo Gentiloni, Wang said.
According to the foreign minister, Eurasia is the main region covered by the "One Belt, One Road" initiative, and the majority of participants represent this region, however, the framework of the initiative will be expanding.
"In fact, China, Russia and Central Asian countries have made significant progress in implementing the One Belt, One Road Initiative".
While China says the New Silk Road is not political, it has run into opposition from India due to a section of it in Pakistan, known as the China-Pakistan Economic Corridor, where some projects run through the disputed Kashmir region.
British Finance Minister Philip Hammond will attend as Prime Minister Theresa May's representative, while Germany and France will be having elections at the time and will send high-level representatives, Mr Wang said.
Wang dismissed those concerns, saying the Pakistan project had no direct connection to the dispute and India was welcome to participate in the New Silk Road. Western leaders were unhappy that the guest list that included Putin and wary of the message China would send with the show of strength.
He said U.N. Secretary General Antonio Guterres, International Monetary Fund Managing Director Christine Lagarde and World Bank President Jim Yong Kim, as well as government officials and experts from about 100 countries, are expected to participate.