Michael Gove is promising to deliver a "green Brexit", which sets global gold standards on policies ranging from pesticides to wildlife protection and animal welfare.
Leaving the European Union provides a "once-in-a-lifetime opportunity" to reform farming, fisheries and land management, the Environment Secretary will say, in his first keynote speech since replacing fellow Brexiteer Andrea Leadsom after the General Election.
Speaking at WWF's Living Planet Centre in Woking, Mr Gove will tell an audience of environmental and countryside organisations that Brexit gives scope for Britain to be a global leader in green policy.
Many of the laws on the environment currently come from Brussels, from agricultural policy and farming subsidies, to air pollution limits, bathing water quality, wildlife protection and climate action such as energy efficiency standards.
Environmentalists have raised fears over the fate of EU regulation on the environment, amid calls in some quarters to cut "red tape" on everything from energy efficiency to protecting habitats.
They have warned that process of transferring rules to UK law must not weaken them, but Mr Gove will move to reassure them Brexit will be a force for good.
"Leaving the EU gives us a once in a lifetime opportunity to reform how we manage agriculture and fisheries, how we care for our land, our rivers and our seas, how we recast our ambition for our country's environment, and the planet.
"In short, it means delivering a green Brexit."
Mr Gove will acknowledge the damage done to the UK and global environment in the past.
"In recent decades we have lost green space, cut down trees, sacrificed meadow and heath land, polluted our earth, air and water, placed species in danger and run down the renewable resources - from fish to soil - on which our future depends.
"And at the same time, across the globe, we've seen climate change threaten both fragile natural habitats and developing human societies, we've allowed extractive and exploitative political systems to lay waste to natural resources and we've placed species of plants and animals in new and mortal danger while gambling with the future health of the whole world."
He will describe himself as an environmentalist because he cares about his fellow animals, draws inspiration from nature and finds its beauty important - but also because of "hard calculation" of the need to protect the natural world or face disaster.
And he will say that Brexit will mean taking back control of environmental policy.
"We now have an historic opportunity to review our policies on agriculture, land use, biodiversity, woodlands, marine conservation, fisheries, pesticide licensing, chemical regulation, animal welfare, habitat management, waste, water purity, air quality and so much more.
"Informed by rigorous scientific analysis, we can develop global gold standard policies on pesticides and chemicals, habitat management and biodiversity, animal welfare and biosecurity, soil protection and river management and so many other areas."
He will also say that a "Government of global Britain" should not just lead on security or trade but also champion sustainable development, be a leader in environmental science and an innovator in clean, green growth.
And Mr Gove will add that it should uphold its pledge to hand over the environment to the next generation in a better condition than it is now.
Tanya Steele, chief executive at WWF, said: "The UK has a track record of leadership in addressing global poverty and climate change, and promoting sustainable development. We need to address global biodiversity loss as an iconic challenge which demands both boldness and ambition.
"So we're pleased that the Environment Secretary is committed to putting improving the environment at the heart of the Brexit process, and ensuring that this country is an environmental leader on the world stage.
"We look forward to seeing the plans and urgent action that will deliver this ambition."
Friends of the Earth chief executive Craig Bennett said: "With all the evidence suggesting that leaving the EU will be a disaster for our environment, Michael Gove must deliver a package of strong environmental regulations if he wants to make a 'green Brexit' a reality.
"Current EU rules aimed at tackling air pollution and climate change and protecting our birds, bees and nature must not be watered down, and mechanisms must be put in place to enforce them post-Brexit."
Mr Gove's speech comes after he told the Commons that UK policy on neonicotinoid pesticides, which have been linked with bee declines, will follow existing EU protections and will be "enhanced in line with the science".
Rebecca Newsom, policy adviser at Greenpeace UK, said Mr Gove had made a "number of promising statements" about reforming farm subsidies, enhancing nature and looking after bees.
"The question is whether and how these words will turn into actual government policy," she said.
"For decades, it's EU environmental law that has cleaned up our beaches, banned dangerous chemicals and held Gove's own department to account for its failure to tackle illegal air pollution.
"Without the bedrock of these regulations and an authority to enforce them, a dirty Brexit will be far more likely than a green one."