The woman in her 70s died at the scene after being hit in the head by falling debris, said Chen Yunbing, a doctor with Ganzi People's Hospital in Sichuan's Kangding county, Ganzi Tibetan Autonomous Prefecture.
Fifteen people were injured, and two residential buildings collapsed, according to authorities of Kangding County.
The quake was measured at a depth of 18 kms and it struck at 4:55 pm (local time) with its epicentre in Tagong Town, 37 kms from the county seat, according to the China Earthquake Networks Centre.
Minor cracks appeared in some airport buildings of the Kangding airport near the epicentre, but flights were not affected, an airport official said.
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About 100 students were in the Zuqing Primary School in Tagong when the quake struck.
Some buildings had cracks but none collapsed and no casualties were reported, said Mao Yu, head of the publicity department of Kangding.
Citizens in Chengdu, the provincial capital, said they felt the quake strongly.
Guo, a Kangding resident, told Xinhua the tremor was powerful and many articles fell to the floor in his home.
Electricity supply was cut off in Tagong Town, said the Sichuan Power Company of the State Grid.
Railway authorities in Chengdu halted passenger trains in affected areas and dispatched workers to check railway facilities after the earthquake. The service later resumed.
The sector of Linzhi county in Tibet Autonomous Region of the G318 Highway, which links Tibet and Sichuan has caved in after the quake.
Local authorities said the traffic is expected to be resumed by tomorrow noon.
A statue of the Buddha in Tagong Temple was damaged during the quake but no casualty was reported, according to the head of the management committee of the temple. The quake also affected Zhaodong City in neighbouring Yunnan province.