Nagqu airport will be at an altitude of 4,436 metres above sea level, slightly higher than the airport in Qamdo town at 4,334 meters, Xinhua news agency reported.
It did not say when the airport would open nor how much it would cost.
Tibet already has five civilian airports, at least two of which are only open for a few months of the year because of extreme weather which makes flying impossible the rest of the time.
China has embarked upon a multi-billion-dollar programme in recent years to revamp old airports and build new ones, especially in the country's remote west, as a way of boosting the economy.
The government has also poured billions of dollars into Tibet, hoping to win hearts and minds in a region the Communist Party has run with an iron grip for six decades.
The government says that the new airports, roads and a railway to Tibet will promote development and help raise living standards.
But Tibet activists say the new links will speed up the pace of Chinese migration there and dilute Tibetan Buddhist culture.
