Trump is due to make a speech at the gathering of international business and political leaders in Davos on Friday.
The demonstrators marched through the Swiss city chanting "Trump not welcome", with some carrying banners and placards reading "dump the Trump" and "Switzerland is hosting Nazis", an AFP reporter said, putting the turnout at over 1,000.
"We are protesting against both Trump and the WEF. The discussions between the richest one percent of the world and a man who fuels an aggressive atmosphere towards women and minorities has no place in Switzerland," said Tamara Funiciello, president of Young Socialists of Switzerland.
The event was joined by anti-globalist and environmental activists, as well as members of Kurdish and Palestinian organisations.
"Trump is the incarnation of sexism, racism, exploitation and corruption," said Michel Zahn, spokesman for the Movement for Socialism.
At the same time protests were held in other cities around Switzerland including Lausanne, where around 300 people gathered in the centre of town with banners and placards.
The American president has faced criticism over his anti-immigration policies and during his election campaign was heard boasting in leaked recordings about groping women.
Trump is set to face a mixed welcome at the Davos gathering, coming up against the defenders of globalization as well as international executives delighted with his controversial tax reforms.