"Chinese spies are often listening these phone calls and putting to use invaluable insights into how to best work the president and affect administration policy," The New York Times said citing unnamed current and former US officials.
Trump, the daily said, uses iPhone to make calls to his friends. He has refused to give this up, despite repeated requests by his officials, who have been asking him to make more use of the secure land lines.
"American spy agencies, the officials said, had learned that China and Russia were eavesdropping on the president's cellphone calls from human sources inside foreign governments and intercepting communications between foreign officials," the daily said.
The White House did not immediately respond to a question regarding the report.
According to the daily, US intelligence officials have determined that China is seeking to use what it is learning from the calls — how Trump thinks, what arguments tend to sway him and to whom he is inclined to listen — to keep a trade war with the United States from escalating further.
"In what amounts to a marriage of lobbying and espionage, the Chinese have pieced together a list of the people with whom Mr Trump regularly speaks in hopes of using them to influence the president," the officials said, according to the newspaper.
"Russia is not believed to be running as sophisticated an influence effort as China because of Trump's apparent affinity for President Vladimir Putin," a former official told the daily.
The New York Times said Trump typically relies on his cellphones when he does not want a call going through the White House switchboard and logged for senior aides to see.
"Many of those Mr Trump speaks with, most often on one of his cellphones, such as hosts at Fox News, share the president's political views, or simply enable his sense of grievance about any number of subjects," the daily said.