Mbappe is among the nominees for the Ballon d'Or, after winning the World Cup with France and helping PSG claim a treble last season.
PSG will host Italian side Napoli on matchday three in the Champions League and Ancelotti praised Mbappe ahead of the Paris showdown.
"Mbappe is a nice player, very fast; but there are a lot of fast players, the difference is he can be both fast and effective at the same time," Ancelotti.
"Whatever he does, he's very effective. He is a no-frills guy, a very direct player. And therefore, very dangerous.
"He is very young, he will definitely be a star in the next few years."
Napoli top Group C with four points from two games, a point ahead of French champions PSG.
In the aftermath of that performance, French midfielder Blaise Matuidi said Mbappe has everything it takes to win the Ballon d'Or in the future.