President Donald Trump's policies, including tax cuts, will provide a big boost to U.S. growth, Blackstone Chairman and CEO Steve Schwarzman told CNBC on Tuesday.

"I think they'll have a substantial impact on the economy," Schwarzman told "Squawk Box" from the World Economic Forum in Davos, Switzerland.

Schwarzman, who led the president's policy forum before it was disbanded, said Trump can take credit for the improved confidence of business leaders and the roaring stock market.

"You started to see this right after the election, and the stock market started going up just in the anticipation of tax reform and tax cuts and changes in regulation," Schwarzman said. "Those things happened and are happening."