According to state media on Monday, the storm tore into coastal Taizhou, a city in Zhejiang province about 250km south of the commercial hub of Shanghai, unleashing torrential rains and high winds.
Fourteen people were killed and 7468 houses were destroyed by the strong winds and rain, the official Xinhua News Agency reported. Eight people were missing, it said.
Total economic losses caused by the typhoon were estimated at $849 million, Xinhua said, citing provincial-level flood control officials.
Along the Zhejiang coast, 814,267 people were evacuated and more than 35,000 ships were returned to ports.
In Shanghai, rain flooded streets, and wind blew down trees and caused minor damage to homes.
An incoming China Eastern flight from Melbourne, Australia, had to be diverted to the southern city of Guangzhou on Sunday night, while dozens of flights were cancelled or delayed on Monday morning. Schools around the city cancelled classes.
By 11am on Monday, Khanun had weakened into a tropical storm and was heading north at about 20km per hour across the province of Jiangsu, according to the Hong Kong Observatory.
With heavy rains expected over the next two days, provincial flood control and drought relief headquarters "urged the local people to prepare for possible mountain torrents and other geological disasters", Xinhua said.
The storm had sustained winds of 155km per hour as it skirted Taiwan on Sunday, according to Taiwan's Central Weather Bureau.
Zhejiang is still recovering from Typhoon Talim, which hit a vast swath of central and southeastern China this month and killed 95 people.