i have seen similar helicopters in several sci-fi movies, but in real life, only V-22 Osprey - a mixture of airplane and helicopter , has similar features. so, is the Scorpion aircraft in movie Avatar a good configuration in real world?

Avatar is a pretty dumb movie so...

Okay, pokes aside, the rotors on the scorpion are probably too small to provide enough lift to keep the aircraft airborne.

According to this source...
Pandora has a lower gravity than Earth, also that vehicle has 2x contra-rotating blades, giving 4 3-bladed sources of thrust. I was unable to find anything on the atmospheric pressure & makeup of the atmosphere, and I don't recall it from the movie. So, maybe

rotor size alone can't decide lift, think of F-35 jet plane which has a very small fan for vtol use, that fan lifts nearly half the aircraft.

https://en.m.wikipedia.org/wiki/Rolls-Royce_LiftSystem
according to this article, the lift fan provides 89kn(nearly 9 tons) of lift.