The 37-year-old woman was attacked by a group of people who were described as being members of the Church of Almighty God religious movement, state media reported. The group preached a global apocalypse would take place in 2012 and has been banned by Chinese authorities.
The attack occurred last Wednesday at a McDonald's restaurant in northeastern Shandong province and was captured on surveillance video, the official Xinhua News Agency said in a commentary. Video footage of the attack was shown on China Central Television on Saturday.
Six alleged group members, including four from one family, have been arrested over the attack, state media reported.
"The audacity of the cult members to terrorize their victim at a McDonald's, a chain frequented by average Chinese, further racked people's nerves," Xinhua said.
Apart from shock and anger, many social media users condemned onlookers, who failed to stop the assault in coastal Zhaoyuan city, about 160 km north of Qingdao.
"If I stay quiet today, who will help me cry for help when I suffer from misfortunes in the future," asked one Weibo user. "If I don't speak up as a passerby, then one day, if injustice should come upon me, no one would speak up for me as well."