The charity says the facelift will see different elements of the bridge examined and repaired.
Britain's best-known industrial monument and the world's first iron bridge is suffering from cracking due to stresses in the ironwork dating from the original construction, ground movement over the centuries and an earthquake at the end of the 19th century.
English Heritage's major conservation programme will involve work on iron radials and braces holding the bridge together, the deck plates and wedges, the main iron arch, and the stone abutments on either side of the Severn.
The cast iron pieces will be carefully cleaned and conserved, re-installed or replaced where "absolutely necessary" and as part of the project, the bridge will be re-painted.
Erected in 1779 over the River Severn in Ironbridge, the historic bridge was the first single span arch bridge in the world to be made of cast iron and was a turning point in British engineering as cast iron became widely used in the construction of bridges and buildings.
Kate Mavor, English Heritage's chief executive, said: "Iron Bridge is one of the wonders of the modern world. An iconic symbol of the Industrial Revolution, it is arguably the most important bridge ever built and without doubt, one of the most important sites in our care.
"This conservation project will ensure that both its revolutionary structure and the story those cast iron arches and beams tell, will continue to inspire us for generations to come."
The conservation of Iron Bridge follows three years of surveys and investigations that conclude this week with engineering experts surveying the bridge, sometimes abseiling from the bridge.
The bridge gave its name to the spectacular wooded gorge that was once an industrial powerhouse.
The Ironbridge Gorge is now a World Heritage Site and the bridge is free to visit.
Work is expected to start on the Iron Bridge in January 2017.