He made the announcement at an energy conference in Pittsburgh on a stage flanked by men in hard hats.
He described the accord as a bad deal and said his pro fossil fuel policies had made the US an energy superpower.
The earliest he can formally start the process of withdrawing the US from the Paris accord is 4 November.
The pull-out will take effect a year later - the day after the 2020 US presidential election – assuming that Mr Trump is re-elected.
The Paris agreement brought together 195 nations in the battle to combat climate change.
It committed the US to cutting greenhouse gases up to 28% by 2025 based on 2005 levels.
President Trump said if he couldn’t improve that deal he’d pull out, but diplomatic sources said there’s been no major effort at renegotiation.
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