The CNBC Fed Survey found 45 percent believing the president will choose Powell in what has become a much anticipated decision, now expected before Nov. 3. Stanford Economics professor John Taylor is the second pick, with 23 percent, followed by former Fed Governor Kevin Warsh, with 17 percent.
But 44 percent of the 47 respondents, who include economists, fund managers and strategists, think Trump should pick Yellen. Taylor is the second choice, with 20 percent, followed by Powell, with 17 percent.
Just 4 percent of respondents want Trump to appoint National Economic Council Director Gary Cohn, a former Goldman Sachs executive once seen as a front-runner for the job.
Yellen was also deemed the best choice by respondents in eight of nine categories in the survey, including best for the stock market, unemployment and managing the Fed's exit strategy, along with managing a financial crisis.
Stanford's Taylor was deemed to be the best candidate for keeping inflation stable.
Overall, Yellen was given a solid B grade by 55 percent of respondents, while 30 percent gave her an A and 18 percent gave her a C or D.