Hi..
I have a confusion about formation of glaciers in antarctica that only small amount of water is converted into ice but not all , however temp. is nearly same there then why only small amt. of ice is there in sea of antarctica region? why not all water?

Glaciers are not formed from ocean water, but from snow that compresses and freezes over long periods.
Do a Google search of 'glacial formation' and there are enough sites discussing it to keep you busy reading for weeks.
The north and south polar regions have different geography, and that determines most of what happens in glacial formation.