In an interview with CNN's Jake Tapper on "State of the Union" Sunday, Pelosi called Trump the "deflector-in-chief -- anything to change the subject."
The California Democrat called Trump's assertions "just ridiculous" and a "smear."
But it's a tactic Trump often uses, she said.
"You make up something and then you have the press write about it, and then you say, 'everybody's writing about this charge,'" Pelosi said. "It's a tool of an authoritarian, to just have you always be talking about what you want to be talking about."
Pelosi also questioned the sincerity of Trump's request that Congress investigate whether Obama wiretapped him.
"And then to take it to the Congress and say, 'you investigate this,' when he's been not in favor of Congress investigating anything, including what do the Russians have on Donald Trump, politically, financially, or personally," Pelosi said, suggesting Trump wasn't serious about his request that Congress look into whether the Obama administration abused its investigative powers during the 2016 campaign.
White House press secretary Sean Spicer announced the President's request in a statement Sunday morning.
"Reports concerning potentially politically motivated investigations immediately ahead of the 2016 election are very troubling," Spicer said, posting the statement on Twitter. "President Donald J. Trump is requesting that as part of their investigation into Russian activity, the congressional intelligence committees exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016.
"Neither the White House nor the President will comment further until such oversight is conducted," he added, without further details on Trump's request.
In her Sunday interview, Pelosi also addressed her claim last week that she'd never met with Russian Ambassador Sergey Kislyak, the diplomat whose meetings with Attorney General Jeff Sessions prompted members of Congress pressure Sessions to recuse himself from all investigations connected to Trump's campaign.
A 2010 photo revealed that Pelosi and other congressional leaders had, in fact, sat at a table with Kislyak and other Russian officials during a meeting with President Dmitry Medvedev.
Pelosi said that meeting was "completely different" than Sessions' meetings with Kislyak.
"We were meeting with the president of Russia," Pelosi said. "He brought an entourage in with him. He was the one doing the talking. The question is, have you met with him. No, I haven't met with him, I met with the president of Russia. Who else was in his entourage? Who knows?"