Hundreds of workers and local volunteers will whitewash the exterior of the landmark for about ten days to protect the building from winter weather.
The Potala Palace was built by Tibetan King Songtsa Gambo in the seventh century and expanded in the 17th century by the Dalai Lama.
The whitewash is concocted using a traditional formula of milk, honey, sugar and lime, and has a distinctive sweet smell.
Painting of buildings on a regular basis is common in Tibet and a necessary protection against extremes of weather.
The palace was included on the UNESCO World Heritage List in 1994.