Workers came to repair a malfunctioning elevator in the northern city of Xi'an on January 30, Beijing Youth Daily cited local authorities as saying.
The crew found the elevator stuck between the 10th and 11th floors, shouted to ask if anyone was there, and cut the power, it said.
The workers left for the week-long Lunar New Year holiday and did not return until March 1.
The deceased woman, 43, reportedly lived alone in building.
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China is prone to safety accidents as regulations and standards are often flouted and enforcement is lax, sometimes due to corruption.
Police investigating the incident found no evidence of trauma and have ruled out homicide, Beijing Youth Daily said.
Last July, a woman was killed after she plunged through flooring over an escalator in a Chinese department store.