I tried a lot of times. But I can't get any end portal frame. I'm using ender eyes to find it but there is nothing. The stronghold is there.

What version are you using? It's spawning fine for me in 0.8.0.

there is a chance that the game freeze when come near to the end portal.

using 0.8.0. mods with IC2, TiC ,COG and NEI
I also find that the freeze of the game means I'm kicked by my own internal server.

Please provide your fml-client-latest.log file and a crash report if possible.

Oh, I found that it is the compatibility issue with oceancraft. when the game freezes, it is near ocean. Also, when end portal is not near ocean, the spawn is OK. the log file also shows something error at oceancraft.

Glad you found the end portal. :)

yeah, that really was the end of this issue