UFC

Naturally he would be crushed against most opponents. He can't utilize his Kung Fu with all the rules of MMA and he would not stand a chance against grapplers and wrestlers once it comes down to the floor. Most people would also probably out class him in stand up. I don't say he doesn't have a fighting chance, but the chance of him winning a MMA fight is most likely very slim.

He would just put out his cigarrete in the Octagon and then double Kick people in the Face knocking them out straight away!!!

Many fighters that train in traditional Asian martial arts will have a problem in modern MMA. Not that these guys are bad but they are not allow to perform a lot of the techniques that they train in. (Example, strikes to the neck, the throat and to the back of the head. They are also not allow to use small joint manipulation and pressure point strikes)

Furthermore,it is uncommon in these styles where fighters have to utilize clinch, underhooks, collar tie etc.... because the Asian styles have a convention that fight takes place at a distance. However, I'm only familiar with karate and Kung Fu, so i don't know how Asian grappling styles look like (example Judo, Aikido etc...)

I think it will be very interesting to see how Donnie Yen will do in MMA. Though people regard the Asian styles as ineffective; Machida and Anderson silva have proven otherwise. George saint pierre have also utilize karate in the octogon but how much of it has he adapted in his fight is not for me to say.

Bottom line, i wouldn't count Donnie Yen out, but he has got to learn the basic styles of MMA in order to protect himself. (Variation of wrestling, jiu jit su, mauy thai, boxing etc... That is if he doesn't know)If he is able to somehow adapted his wing chun (and other styles that he knows)successful in the octagon,he'll be a force.

I'm kind of surprised seeing many of the responses in this thread considering that out of the majority of martial arts actors, Donnie Yen is actually in better athletic shape then many of them.

Compare him to Jet Li, who is much smaller than Donnie Yen and is nowhere near as fit.

Also, has anyone on this topic seen Flashpoint? Clearly Donnie is aware of MMA and must like it to a degree, because all of the fight scenes in Flashpoint are MMA and not traditional Wushu. He also uses plenty of kickboxing and some ground grappling in Killzone (Sha Po Lang).

This isn't to say that Donnie is a real life expert in these styles, however the fact that he has a combination of greater physical fitness/height/muscle mass over many other Wushu actors and that has been willing to study them for films leads me to believe that he would do better than many would suspect in MMA.

He would have to prepare heavily for it, but I think that out of many of the current martial arts stars, Donnie is one of, if not the most adept for real competition.

"Bulls**t MR.Han Man!!"--Jim Kelly in Enter the Dragon

It doesn't really matter how fit he is, there is no way that he'd stand a chance against UFC fighters, against guys in smaller organizations maybe, but the fact that he's almost 50, no matter how good a shape he is, those younger fighter are trained to be professional fighters not wushu stylists who are actors.

you are wrong on a few points
1. he does have grappling skills and has practiced judo and jui jitsu. so you cant say he would lose in grappling
2. no on in the ufc can out strike him.
he is an expert in striking and has used his skills on the streets of boston when he was a teen in gangs.
3. he is amazingly fast. faster then anyone in the ufc.
he has practiced various forms of kung fu. muay thai, tae kwon do and various other styles of striking.

all in all if he trained to mix his striking with his grappling he may vary well do good

Don't be naive. He's 48 and even though he might be a talented martial artist, there is a HUGE gap between people like him and actual professional fighters. Especially MMA fighters.
I read something about him weighing around 70kg/154lbs, so he would probably fight in the leightweight division of the UFC. This division, right now, is the most stacked division in the UFC and I'd bet 1000€ that he wouldn't stand a chance against any of the Top 10 contenders in that division.

Don't get me wrong, I really like Donnie, enjoy his movies and have tons of respect for him as a martial artist, but saying that he would even have the slightest chance of winning an MMA fight against a professional is just ridiculous .

Oh and stating that "NO ONE on the UFC can outstrike him" is complete BS. I'd really like to see how a 154lbs / 5'8 guy outstrikes Jon Jones, Anderson Silva, Shogun Rua, Junior Dos Santos etc.

he's old and has 0 mma experiance, it is completely different than streetfighting or any tma, maybe he could beat nobodies in smaller shows but anyone in the ufc in his wieght class would finish him inside of 1 round.