Typhoon Soulik was set to dump up to 18 centimetres (seven inches) of rain on eastern parts of China in just 24 hours, forecasters said Sunday, a day after the storm killed two when it battered Taiwan.
The typhoon was downgraded to a tropical depression at 05:00 am (1100 GMT) as it swept inland, and "its strength will continue to weaken", the China Meteorological Administration said on its website.
It set the typhoon warning at blue, the lowest of four levels, after windspeeds dropped from 118 kilometres (73 miles) per hour when it first struck the coast of Fujian, to 58 kmh as it passed over Jiangxi province.
More than half a million people had been evacuated from Fujian and Zhejiang provinces as the typhoon approached, with 5,500 soldiers deployed to carry out relief work if needed.
While Soulik had earlier caused havoc in Taiwan, tearing roofs from homes, causing landslides that blocked roads and leading to the cancellation of 350 flights, effects on the mainland were less severe.
Waves up to 10 metres high pounded sea defences in Ningde city when the storm reached Fujian province on Saturday afternoon, Xinhua news agency reported.
"Billboards have been shattered and trees have been uprooted", it said, adding that almost 31,000 ships were called back to port and 20 flights were cancelled.
Rains affected 410,000 people in the major Zhejiang city of Wenzhou, causing a "direct economic loss" of 210 million yuan ($34 million), the agency said.
In Taiwan two people were killed, one is missing and 104 were injured in the storm.
One town in central Taiwan reported "widespread" landslides and floodwater levels a storey high.
The northern village of Bailan saw the heaviest rain, with 90 centimetres (35 inches) falling in 48 hours, with winds gusting up to 220 kilometres per hour.
Downpours have hit wide swathes of China over the past week, affecting two million people in the southwest.
The death toll from a rain-triggered landslide in southwestern Sichuan province last week rose to 43 late Saturday after more bodies were retrieved, Xinhua reported.