Three men have been detained in connection with the incident, which led to protests by the leader’s supporters.
Ms Mayawati is famous for building statues of herself and other icons of her low-caste Dalit community.
Most of the statues are in the state capital, Lucknow, with some scattered around other cities in Uttar Pradesh.
Critics accuse her of self-glorification and wasting public money. She accuses them of conspiring against her.
She lost her post as chief minister in March 2012 after her party was defeated in state elections.
Police said the unidentified men had broken the head and damaged the arms of a statue that was almost 4ft (1.2m) high in a park in Lucknow.
A little-known organisation called Uttar Pradesh Nav Nirman Sena claimed responsibility for the incident, saying it was a protest against “corruption” during Ms Mayawati’s regime.
Within hours of the incident, the Uttar Pradesh government said the statue would be replaced with a similar one.
A similar statue of the leader was found in the store of a cultural academy and taken to the park and installed overnight