Roma meet the Rossoneri in the quarterfinals.
Ranieri said: "The objective is to do well against Milan. We know that at home they have not lost in 12 games, the last one was against Napoli. Since (Sergio) Conceicao arrived they have had five wins, two draws and two defeats. We are going to face a team full of talent and champions.
"We want to do well and get through to the next round. We are aware that we are facing a great team and we will try to play our game.
"I expect a difficult match but we are ready to face a great team. Milan can explode, they can play in attack, they have quality players."
Ranieri also admitted he was aware of rumours of Roma making a contract offer to Real Madrid coach Carlo Ancelotti about next season.
He said: "I read. But every day something new comes out and it is right that it is so. We are focused on our work. The new course has been announced.
"For the name we will wait until the end of the season. All the rumours that come out do not come from us."