CCTV footage shows the policeman repeatedly punching Brandie Redell, who admits that she was trying to shoplift around $388 of women's clothing from a department store in Davenport, Iowa.
When she was caught and questioned by police she says that Officer Scott Crow beat her so badly she was hospitalised with an eye swollen shut and vision that is now 70 per cent impaired.
The surveillance footage, released by civil rights group, the Better Government Association, shows Officer Crow appear to lunge towards the mother and punch her several times in the head. Another officer holds down the women's legs.
A store worker runs from the room with Ms Redell's one-year-old child at the start of the attack, which lasted for over a minute.
"I was asking him why was this happening and I was crying. I was screaming, begging for someone to help me," Ms Redell told WQAD.com.
Officer Crow wrote in his report that the woman bit him, something that the women admits she did, 'to try to get him off of me'.
Ms Redell, who has two previous shoplifting convictions, is due in court on August 23. Ms Redell is now working with Chicago civil rights group Living And Driving While Black Foundation.
They are planning on a suit against the Davenport Police Department.
Davenport Police Chief Frank Donchez said: "Our policy says you are to conduct yourself in a professional manner.' Was he within policy? No. Do we need to conduct an internal investigation? Yes."