The cave-in trapped 18 vehicles, reported Xinhua.
Another 30 people were receiving treatment in hospital and were not in life-threatening situations, said authorities in the city of Meizhou.
The cave-in happened around 2.10 am on a section of the Meizhou-Dabu Expressway in Meizhou. The cave-in area measures 184.3 square metres, according to the government of Meizhou.
More than 500 people have participated in the rescue.
--BERNAMA-XINHUA