The peatlands near Doncaster in South Yorkshire are part of the largest lowland peat bogs complex in the UK, according to Natural England.
The bogs have been under restoration since commercial peat extraction stopped at the site in 2003.
Natural England representative Jeff Lunn said: "Initial restoration is proving successful but the bog needs further long-term restoration."
The £2.2m grant will see restoration work for the bogs, plus research and monitoring for the next three years.
"The money will help ensure the peat is wet enough so that wildlife, including birds such as the nightjar and the hobby and specialist plants including cotton grass, bog moss, bog rosemary and wild cranberries can thrive," he added.
Extraction became mechanised in the 1960s by Fisons for horticultural purposes and latterly by Scotts UK. In 2001 an agreement between Scotts UK and English Nature ended large-scale peat production and extraction ceased in 2004 within the boundary of the SSSI after the Government paid Scotts £17m for the peat extraction rights at the Thorne Moors site.
Restoration of the site by English Nature helped by Scotts has included the creation of compartments with peat bunds so that water can be carefully controlled.