-- A construction worker from western China, Yi Changming, hopped a bus to Tibet looking to see the far reaches of his booming country and hoping to make some money.

Six months later and 750 miles from home, he has steady work building houses and a circle of Tibetan friends to drink and play cards with. But he's bothered that people like him, members of China's majority Han ethnic group, dominate economic life in this restive region, leaving most Tibetans to scrape by farming and doing odd jobs.

"It's because there aren't enough Tibetan bosses," Yi said, as he sat with his new friends in Tibet's dusty capital, Lhasa. "All the bosses are Han Chinese. They come here with capital. They come here already knowing how to do business. The Tibetans don't have the same economic culture."

China's muscular brand of capitalism is roiling Tibet as much as anything else in five decades of communist rule. And despite official promises to lift ordinary Tibetans out of poverty, it is threatening to leave them behind.

Already, Tibet's cities look like Chinatown anywhere, with mazes of restaurants, clothing shops and hardware stores, almost all Han-owned.

Traditional Tibetan society, remote and isolated atop its forbidding Himalayan plateau, is based on farming and herding. Today's Han migrants are poor by Chinese standards, but they come with business skills learned in China's hectic, sprawling markets and cities.

"Tibetans can't keep up. Han Chinese just think differently," said Dawa, an art gallery owner in Shigatse, Tibet's second-largest city and home to the majestic Tashilunpo Monastery. Like most Tibetans, she uses only one name.

Dawa, 24, is a rare success story in Tibet. She went to work in a restaurant when she was 8 and opened her own place when she was 20. A year ago, she used the profits to open an art gallery that sells oil paintings and tapestries to Shigatse's growing armies of tourists.

"If we want to compete, we have to develop our own products and skills," she said.

Tibet, which is about three times the size of California, has been ruled by China since 1951, when its troops occupied the territory. Tibet's spiritual leader, the Dalai Lama, lives in exile in India.

Tibet campaigners abroad warn that it is becoming a quasi-colonial society, with Han holding all the powerful posts and Tibetans living as second-class citizens.

Beijing pours billions of dollars a year in subsidies into Tibet, but critics say the Han get most of the benefits.

Chinese rule and Han migration are "eroding the fabric of Tibetan society," said Thierry Dodin, director of the London-based Tibet Information Network.

More Han are expected to pour in looking for wide open spaces and frontier opportunities when a 1,220-mile railroad linking Tibet to the rest of China opens in 2007.

Chinese officials in Tibet deny there is mass migration, even though visitors can easily see thousands of Han workers chatting in various Chinese dialects and wearing more citified clothes than their Tibetan neighbors. The officials say they are merely a "floating population" and refuse to give numbers.

They deny there's a wide income gap, and if there is any disparity, it's because Han work in service industries and Tibetans in farming, said Xu Jianchang of the Tibetan regional government's Reform and Development Commission.

"That's why their income levels are different. You cannot compare them," said Xu, who, like most officials here, is Han. "Given these factors, it is inappropriate to say there is an income gap."

According to government statistics, rural Tibetans have the lowest average income in China -- $180 a year in 2002, a tenth of the average in booming Shanghai, 1,800 miles to the east.

But as China's economy surges, some wealth is trickling down.

"Life is getting better and better," said Pemba, a Tibetan farmer.

Unable to read, he rides his bicycle cart an hour into Shigatse each day to sell cabbages, melons, carrots and chives by the road. His customers are better-off Chinese migrants, traders and middlemen.

"Incomes are rising, and my two children both go to school," he said.

Dawa, the art gallery owner, is one of eight children and speaks Tibetan and Chinese but says she can't read either language. "I always worked," she said. "I never went to school."

Her art gallery hasn't broken even, but she's counting on Tibet's newcomers to get her there.

"There are more and more tourists coming to Tibet, mostly Han Chinese," she said. "They're the ones with the money."

Tibetan markets are being inundated with experienced migrant laborers.