by the way if you didn't know he will flee at 0:00 if you have dealt enough damage, so
carry on right till the end of the quest. Heres alot of ways to beat him.

http://monsterhunter.wikia.com/wiki/Shen_Gaoren_Guides

you should use a long sword wiyh high fire attribute, it is the best way to literaly kill
it.

use hammer or anything with high damage and always aim for its legs

pick any weapon with high dragon attribute(prefer long sword or hammer) aim 4 the legs and
when he falls go 4 the head(bring 2 large barrel bombs+ and 1 small time bomb + with
u,place the big ones near the head leave the small one and run)then go back and try
getting as many hits as u can.use ballistra S and dragonator also cannonball S that u can
find where u start if u move as left as u can.good luck