He called the shift in population a "form of cultural genocide".
In Lhasa, the region's ancient capital, there are now 100,000 Tibetans but twice as many outsiders, he said.
The majority of those are Han Chinese, the country's ethnic majority.
He also said that an extra one million more people are expected to settle in Tibet after this summer's Olympics, but did not say how he received this information.
The Dalai Lama urged the world community to help resolve the crisis in Tibet.
"We have no power except justice, truth, sincerity... that is why I appeal to the world community to please help," he said.
The Dalai Lama reiterated that he wanted to open a dialogue with the Chinese leadership. "My side is open... we are waiting," he said.
Tour by diplomats
The Dalai Lama’s comments comes as diplomats prepare to leave Lhasa after a quick overnight trip.
About two dozen diplomats, including those from the United States, Britain and Japan, visited the Tibetan capital but the Chinese foreign ministry did not reveal details of their agenda.
The government-organised trip is the latest move by Beijing to show that it has restored order in the region after deadly anti-government protests more that two weeks ago.
China blamed the unrest on the Dalai Lama, who has been based in India since fleeing his homeland decades ago, and his supporters.
The protests in Tibet, and other regions with large Tibetan populations, brought unwanted attention on China and its human rights record ahead of the Beijing Olympics.
China hopes the Olympics will showcase the country as an emerging international power and an important player in the international community.
The Tibet protests, led by monks, began peacefully on March 10, on the anniversary of a failed 1959 uprising against Chinese rule.
Tibetan exiles say about 140 people were killed in the recent protests while Beijing puts that number at 22.