The army was originally painted in bright colours.
The new dig will be the third since the tomb was first uncovered by accident in 1974 by peasants digging a well outside the western city of Xi'an.
The excavations will focus on a 2,000m square patch lying within the tomb's main pit that holds the main warrior force.
It is thought the terracotta army was produced to protect the emperor in the afterlife.
Qin, who died in 210BC aged 50, created China's first unitary state by conquering rival kingdoms.
To control his empire he built an extensive system of roads and canals, while unifying standards of measurement and establishing a single written language and currency.
He ruled China with an iron first, wiping out anyone he believed would challenge his rule, and was obsessed with immortality.
His mausoleum under an artificial hill close to the site of the terracotta army has never been excavated.
The chamber containing the emperor's body is rumoured to be protected by elaborate booby traps and contain a model of his empire complete with seas and rivers flowing with mercury.
Most of the designers and construction workers involved in building the tomb are thought to have been buried alive with the emperor to protect the structure's secrets.