Hello, i am using Arduino Mega to comunicate with another devices with RF, I need to use a serial interruption in Mega, because I need to save in a vector array, somebody can help me?
Your question doesn't make sense.
What does a serial interrupt have to do with saving an array?
Tell us more.
Serial is already handled by an interrupt. All you need to do is read from it and save into your variable.
Have a look at the examples in Serial Input Basics - simple reliable ways to receive data.
Please explain what you're actually trying to do. A complete picture of the problem you're trying to solve, not the solution you're trying to implement (which may or may not be a good solution in the first place).