chinese kungfu, karate, ufc, mma, boxing, which is the most powerful?

[Ignatius]

Um, UFC is a showcase of MMA, which is a combination of any of the other forms you've mentioned, so this question doesn't make the most sense.

I'd say the strongest fighting style though would have to be some type of MMA, which has the potential to combine the most effective moves from all other martial arts styles.

[MonkeyBalls]

UFC of course is not is fighting style, Mixed Martial Arts could be any combination of anything.

So the only arts you really have on there are Kung Fu, Karate, and Boxing. All which involve primarily striking.

As MMA has demonstrated, a successful fighter needs to have good grappling skills, whether or not he prefers to grapple or strike. If he prefers striking, then he uses his grappling ability for take-down defense, and to continue to fight and/or try to get back up if and when he is taken down. A stand-alone striker has no chance against someone who is well-rounded.

If I had to pick only one style, by far the most pressing would be grappling.

[BarraganL]

"UFC isnt a fighting style, but a company that host mixed martial arts events. Also MMA could be any combination of martial arts in the world"

Do some research before you ask

[Essex]

UFC is not a style of fighting or martial arts. It's a promotion

[danielh]

They are all powerful, it all depends upon the person, not the art.

[Desk3Bound]

The most 'powerful' methods of fighting are not on your list, they would be: Catch Wrestling, Pankration, and Tae Kwon Do.