The BJP has nominated Modi as its candidate for Prime Minister's post, but the Gujarat CM has so far behaved as a "hukumshah" (dictator), he said.
Chavan was addressing a joint Congress-NCP campaign rally here in southern Maharashtra.
The Congress leader said Modi coming to power at the Centre would be "harmful" for the country.
Chavan took a dig at BJP's high-tech poll campaign, saying the saffron party was taking people for a ride in the name of technology.
The alliance between Sharad Pawar's NCP and Congress has been forged to keep communal forces out of power, the Chief Minister said.
Union Home Minister Sushilkumar Shinde, who is contesting from Solapur Lok Sabha seat, also spoke on the occasion.
