It happened Saturday afternoon inside a Mercedes dealership's waiting room.
Police say Fei Du was watching the sexually explicit video on a computer owned by the dealership.
According to police he motioned for the girl to come watch with him.
The mother of the child, 45, observed the encounter, removed her daughter from the waiting room and called 911.
Fei Du is charged with public display of sexual material and endangering the welfare of a child.