What is the different between two of this?
What's the different between "He is my idol" and "He is an idol of mine"?
both sentence have the same meaning instead? And when i have to use the first one, and when i have to use the second one?

Question

Answer

They mean relatively the same thing. The difference is the first one, "He is my idol", gives the impression that 'he' is either your only idol or your main idol. The second one, "He is an idol of mine", gives the impression that you have multiple idols and 'he' is just one of them.