The 14th typhoon of the year crossed into Guangdong Province's coastal towns of Chencun and Maoming, from where tens of thousands of people had been evacuated, Xinhua reported.
Authorities also had recalled more than 50,000 vessels and about 200,000 sailors and fishermen to ports.
In the island province of Hainan, several schools were ordered closed.
Heavy rains were forecast in regions along the storm's path.
Hagupit was blamed for the deaths of at least eight people in the Philippines, including three who died in a landslide, CNN reported. One person was electrocuted and four others drowned.
Another 15 people were reported missing by the Philippines National Disaster Coordinating Council. The storm also damaged about 840 homes in the Phillipines.