President Trump said several times he would impose 45% tariffs on Chinese exports to the U.S. market once he became president. See:

Donald Trump Says He Favors Big Tariffs on Chinese Exports

By MAGGIE HABERMAN January 8, 2016: 

But he backed down a few times. See: http://cn.nytimes.com/world/20160108/c08first-draft-donald/en-us/

Donald J. Trump said he never suggested imposing a 45 percent tariff on Chinese goods.: https://www.nytimes.com/interactive/2016/us/elections/fact-check.html?_r=0&_ga=1.166668024.73202110.1474360137#/factcheck-64

Asked about his proposal for a 45 percent tariff on Chinese goods, Mr. Trump said, “I don’t even know where the 45 percent came from.”: https://www.nytimes.com/interactive/2016/us/elections/fact-check.html#/factcheck-49

 

See also:

ECONOMIC TRENDS

How a Tariff on Chinese Imports Would Ripple Through American Life

By MICHAEL SCHUMAN April 8, 2016, http://cn.nytimes.com/business/20160408/c08up-trumptrade/en-us/

Experts Warn of Backlash in Donald Trump’s China Trade Policies

By BINYAMIN APPELBAUM May 3, 2016 http://cn.nytimes.com/usa/20160503/c03trumptrade/en-us/