The older sister of victim, Ailun, said on Sina Weibo, the Chinese equivalent of Twitter, that Ma was electrocuted while trying to answer a call on her iPhone while the device was charging, Xinhua reported.
"(I) hope that Apple Inc can give us an explanation. I also hope that all of you will refrain from using your mobile devices while charging," her post read.
The post has gone viral online, with many forwarding the message and warning others of the dangers of using mobile devices while they are being charged.
Ma's father, Ma Guanghui, confirmed that his daughter was electrocuted, adding that her body showed signs of electrocution.
Ma, a resident of Xinjiang's city of Changji, was previously employed as a flight attendant at China Southern Airlines.
Ma's sister said she hopes to seek justice from Apple.
Apple said Sunday the company felt "deeply sorry for the unfortunate accident" and expressed condolence to the victim and her family. It said it would have a thorough probe into the case.