The official Xinhua News Agency said the magnitude-5.7 quake hit Saturday morning and was centered in central Jiangxi province's Ruichang city near the border of Hubei province.
Most of the damage occurred in Ruichang and in the popular resort town of Jiujiang, it said. Several counties in neighboring Hubei were also affected. Hundreds of buildings were destroyed and thousands damaged, Xinhua said.
Chinese Central Television news showed rows of crumbled brick buildings and deep cracks in the walls of buildings still standing in Ruichang.
The news showed a young boy with his head heavily bandaged and a man crying on a bench as he cradled an injured leg. An old man and his injured wife shared a cot at a makeshift medical center set up in the street.
Many people in Ruichang, which has a population of about 420,000 people, were staying outside for fear of more aftershocks and 1,000 tents were being sent to the area, Xinhua said.
Temperatures in the region were relatively mild, hovering around 10 degrees Celsius (50 degrees Fahrenheit), weather reports said.
The United States National Earthquake Information Center reported the quake had a magnitude of 5.5, AP reports.