Passengers who had already boarded the plane were asked to get off, as mechanics searched to determine if any coins were left inside the engine.
Crews recovered one coin that landed inside the engine and eight more in the surrounding area during the inspection, which lasted about five hours.
The pilot said serious damage, including engine failure, can occur if metal is sucked into the engine.
Police confirmed Qiu, who was traveling with husband, daughter and son-in-law, did not have a criminal record or any indication of mental illness.
China Southern Airlines said activities that threaten passenger safety are prohibited and the incident remains under investigation.