The girl needed hospital treatment for a wound to her thigh after the incident in Dawson Park, Dundee on Saturday evening.
Police have appealed for dog walkers who use the park to contact them in an effort to trace the animal's owner.
They appealed to anyone in the area who may have seen the attack to contact them.
The appeal lead to wardens seizing the dog from a house in the Douglas area of the city yesterday.
A 22-year-old woman has been charged in connection with the incident and a report will be sent to the procurator fiscal.