The front part of the car was slightly damaged in the stone-pelting, but none was injured, police said.
Panneerselvam, who has revolted against the ruling AIADMK leadership, was proceeding towards Andipatti in the district, his native, when the incident occurred.
He was here to take part in various functions organised by his supporters.
Police said they were searching for the miscreants who pelted stones at the former chief minister's car.