The quake struck at around 5.43 pm (local time) at a depth of about 10 km, the China Earthquake Networks Centre said.
The tremor was felt strongly in Chongqing's city districts such as Yubei and Shapingba, the state-run Xinhua news agency reported.
The municipal earthquake administration has sent experts and rescuers to the quake zone.
Wulong is home to the scenic area Wulong Karst, which was named as a world natural heritage by UNESCO in 2007. Some scenes for the Hollywood blockbuster "Transformers 4: Age of Extinction" were also filmed in the area.