The storms hit Yancheng city in the province around 2:30 pm (0630 GMT) on Thursday, levelling homes, it said.
Winds of up to 125 km (77 miles) per hour struck the city and outlying suburbs, destroying numerous houses, according to the report.
Photos of the scene show dazed residents near homes reduced to rubble amid tangled telephone wires, splintered wood and toppled poles.
Many parts of China have been lashed by torrential rains this week as summer rainstorms have been heavier than usual, causing damage across the country.
Flooding is common during the summer monsoon season in the south of China but precipitation has been particularly heavy this year.
In central China heavy floods killed 22 people and displaced 197,000, state media said on Monday.
Eight people were trapped in a flooded coal mine in southwest China's Guizhou province, Xinhua reported.
Direct economic losses from the floods hit nearly 2.7 billion yuan ($410 million), state media reported.