The fire started at about 2:09 pm Sunday in the forest on the Mt. Yangmei in the Yi Autonomous County of Shilin, a spokesman with the county government said.
About 30 excavators, loaders and bulldozers and 60 pumps have been used to fight the fire. In addition, a helicopter was dispatched Tuesday morning to spray water over the forest, the spokesman said.
"But the lack of water due to a lingering drought and strong winds have made the operation more difficult," he said.
"For most of the time, two fire-fighters have had to carry a bucket of water between them on their shoulders while climbing up the mountain until they reached the fire, which consumed lots of time and energy," he said.
The fire is still spreading, he added.
The cause of the fire remains unknown.
Also Tuesday, more than 2,000 fire-fighters and local villagers were trying to contain a fire in the Yushe National Forest Park in Guizhou Province that neighbors Yunnan. The fire has been raging for a day.