The storm is the third major tropical system to hit Taiwan in the past two weeks.
More than 900,000 people in southern and eastern Chinese provinces had earlier been relocated, including some 540,000 people in Fujian, Xinhua said, citing government officials.
In Zhejiang province, nearly 300,000 people had been evacuated to safety and 27,704 vessels called back to the harbour.
In Guangdong, around 70,000 people, including fishermen and residents in low-lying areas, had been evacuated.
Chinese meteorologists have issued the highest-level warnings for Sepat, which was moving northwest at a speed of 15 to 20km per hour and was expected to hit Jiangxi province on Sunday afternoon.
Expressways in Fuzhou, the capital of Fujian, were closed, while 109 domestic and international flights at the city’s airport were cancelled on Saturday.
Xiamen and Jinjiang cities also cancelled outbound flights, Xinhua said.
The ministry of civil affairs has sent 3,000 tents to evacuated people in Fujian.
Disaster officials in the Philippines said three people drowned in flooding after Sepat exacerbated monsoon rains in that country.
Nearly 550,000 people were affected by floodwaters in Manila and the northern provinces, and more than 3,500 people were sheltering in evacuation centres.
Parts of the capital and surrounding provinces remained under water on Sunday.
Taiwan’s disaster centre said 27 people had been hurt in the typhoon.
About 2,500 people were evacuated and nearly 9,000 homes were still without electricity.
Wide swathes of China have been plagued by near-constant torrential downpours since the summer rainy season began.
Rains brought by tropical storm Pabuk in south China‘s Guangdong province earlier in August affected more than one million people and destroyed thousands of houses, Xinhua has said.
According to the latest government figures, extreme weather killed 712 people and left 163 missing across China in July alone.