The landslide happened at 5 p.m. local time, Xinhua reported. Two women have been rescued from the debris as more than 400 rescuers search the area.
Megi made landfall earlier Wednesday in China's Fujian province, less than 24 hours after it devastated Taiwan.
Four people died and at least 524 were injured in Taiwan after the powerful storm slammed into the island's northeastern coastline on Tuesday afternoon.
More than 3.8 million homes were left without electricity on Tuesday night after some 38 inches (one meter) of rain fell in Yilan County, according to Taiwan's Central News Agency
By Wednesday, more than a million
were still waiting for their power or water to be restored, with the total damage toll sitting around $4.78 million.
The typhoon was the third storm system
to hit the island in just two weeks, lashing Taiwan with winds up to 143 miles per hour (230 kilometers per hour).
On September 14, Typhoon Meranti killed two people and injured 63 in the island's south, followed by typhoon Malakas which drenched Taiwan's north on September 16.
Typhoon Meranti was the strongest storm seen in the region
since 2013, leaving hundreds of thousands of Taiwanese homes damaged or without power in its wakes.
Flash flooding, mudslides possible for China
Typhoon Megi reached the Chinese coastline at around 2 a.m. local time on Wednesday, CNN meteorologist Michael Guy said, already less powerful after its passage over Taiwan.
"(Since its second landfall) it has weakened rapidly," he said. "Even with the weakening, the storm will continue to dump heavy amounts of rainfall over the region for the next 24-48 hours, possibly an additional 100-250 millimeters of rainfall."
Guy said flash flooding and mudslides were possible as heavy rain continued to pelt southeastern China.
It comes just two weeks after Typhoon Meranti
, the strongest storm in the region since 2013, left seven people dead in Xiamen Province and several others missing.
Flights, trains to resume
A spokesman for Taiwan's Central Emergency Operations Center told CNN on Tuesday night most of the injuries had come from traffic accidents and flying objects, thrown about by extremely strong winds.
"Stay home and reduce unnecessary going out," the spokesman said. "The effect of the typhoon will impact us until tomorrow morning (local time)."
He said 1,400 people had been evacuated from the country's mountainous areas. The typhoon made landfall at 1.30 p.m. (1.30 a.m. ET) on the island's less heavily populated east coast.
Taiwan's train services were planned to resume on Wednesday, while Taiyuan International Airport
said it was planning to work overtime to fly out more than 120,000 passengers after flights were canceled on Tuesday.