Juve have been regulars in the final stages of the competition in recent years, even reaching the final of the 2016-17 edition, but found Real Madrid too strong for them on that occasion.
Having added Ronaldo to their ranks this summer in a €100 million (£89m/$114m) deal, the former Italy Under-21 striker is confident that the Portuguese will give them the extra dimension they require to go all the way.
"Of course he will help them in the Champions League,” the ex-Bianconero told Goal . "He will help them in tournaments and also in an economic way. He will be great in Serie A and is a great talent and champion.
"Juventus are one of the best teams in Europe, and of course they are a leading contender to win the Champions League."
Despite the Italian top flight having widely been perceived to have strengthened this summer, with signings such as Ronaldo, Amoruso still believes that Juve are the team to beat.
"Serie A teams need big stars to compete in the Champions League, and now they have Ronaldo, and I think more players will come in the future," he said. "The teams are now stronger than in the past five or 10 years.
Ronaldo, who said joining the Turin giants was an easy choice , has already made a promising start to life in Italy, netting on his debut in a friendly win over the club's Primavera side .
Amoruso also gave his opnion on Mohamed Salah's move to Liverpool last summer, insisting the Reds were given a "gift" in the low fee paid for the Egyptian star.
He added: "Salah is a very big talent and I don't know why Roma sold him so quickly and for such a low fee. They gave a gift to Liverpool!"