19 year old Diana Metellus was charged with assault, reckless endangerment, endangering the welfare of a child, criminal possession of a weapon, menacing and harassment.
Metellus, of Fort Myers, Fla., will be arraigned later Thursday in Downtown Brooklyn.
Police say she is suspected of beating the girl with a belt after she wandered off from the building last Wednesday.
Other charges are possible and the investigation continues.
The girl, also from Florida, fell from the sixth floor apartment after the attack. She remains hospitalized.
The girl's 1-year-old stepbrother was taken into custody by the city's Administration for Children's Services after a family court hearing.