The quake struck Jinkouhe District in Leshan City at 1:21 pm at a depth of 14 kms, said the China Earthquake Networks Centre (CENC) said.
About 11,000 people were affected with more than 2,000 houses damaged. Traffic and telecommunications in the quake zone have been restored to normal.
The People's Hospital in Jinkouhe received two calls for assistance, both regarding slight injuries, state-run Xinhua news agency reported.
Many Leshan residents rushed into the streets and students assembled in school playgrounds.
"I felt strong tremor and then ran out of the office," Peng Tao, a tobacco company employee in downtown Leshan, about 68 kms from the epicentre said.
Railway authorities have ordered four passenger trains and 10 cargo trains near the region to stop in safe sections and railway workers are checking the rails.
Covering an area of 598 square kilometres in southwestern Sichuan, Jinkouhe District is home to about 60,000 people, including many of the Yi ethnic minority.