Haridas Shende, an ABVP activist, missed the target, and was beaten up by some people present at the venue and handed over to the police.
Kumar, who is out on bail after arrest on sedition charges by the Delhi police, today paid tributes to Dr Babasaheb Ambedkar at the Deekshabhoomi here on the occasion of the iconic leader's 125th birth anniversary.
He later spoke at a program organised by Rashtrawadi Youth Congress and others.
Shende then hurled a slipper at Kanhaiya, but missed.
Earlier in the day, when Kanhaiya who was received by Rashtrawadi Youth Congress leader Salil Deshmukh and NCP MLC Prakash Gajbhiye, a group of Bajrang Dal activists pelted stones at his car near the airport.
In his speech, Kanhaiya said such "undemocratic and intolerant" incidents did not deter him. "You can't scare me off by throwing stones and shoes at me," he said.