More than 32,000 boats were recalled by late on Saturday as fishermen were ordered back into port and tourist activities were cancelled in Zhejiang, Xinhua said.
Vacations for flood-control workers were cancelled in Shanghai, where the Special Olympics and the Chinese Grand Prix were under way, and plans to drain competition sites were being drafted.
A spokesman for Taiwan's central weather bureau said: "The power of Krosa ... has been reduced to a tropical storm after it made landfall on the northeastern tip of the island."
Two men were killed in a Taipei suburb when their house was buried by a landslide, the Disaster Relief Centre said in a statement.
Isolated accidents caused by high winds killed another three.
Two men were missing, including one who was buried in debris after a hostel was hit by a landslide in Hsinchu.
At its peak, Krosa caused a massive power cut blacking out more than two million homes and businesses in Taiwan, the fire agency said.
The storm led to the cancellation on Sunday of 378 flights and the government continued to advise people against going to work or school.
Tropical Storm Risk, a British typhoon-tracking organistaion, said Krosa was expected to weaken late on Sunday, before heading northeast toward Fukuoka in Japan.
Zhejiang officials said parts of the province had already suffered torrential rain.
Meanwhile, floods and landslides triggered by Typhoon Lekima, which battered Vietnam's central coast earlier this week, killed up to 34 people and left 19 others missing, officials said on Sunday.
Thanh Hoa and Nghe An provinces were hit hardest by torrential rains, with strong winds blowing off roofs and floods submerging entire villages.
Nguyen Xuan Hanh, an Nghe An provincial official, said: "We have not seen flooding like this in 20 years. It was so fast and so out of the blue."
On Saturday, helicopters dropped food to stranded villagers while rescue workers waded through chest-high water to assist people to safety.
The government said preliminary damages from the typhoon, the fifth of 2007, stood at $41m after the storm and floods destroyed about 100,000 homes, mainly in central provinces.