The president said this would put an end to the "war on coal" and "job-killing regulations".
The Energy Independence Executive Order suspends more than half a dozen measures enacted by his predecessor, and boosts fossil fuels.
Business groups have praised the Trump administration's move but environmental campaigners have condemned it.
Outside the White House, a few hundred protesters gathered to vent their displeasure at the executive order.
Inside, the president was flanked by coal miners as he signed the order, saying: "My administration is putting an end to the war on coal.
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