"P. Alves" wrote
My mother gave me one orchid (it is my first orchid I have to say) and
It was full of flowers and had 6 green leaves. After 3 months the
flowers are still there but the leaves died one by one and only one is
left. they start to get yellow and then ...

See the picture in
http://i90.photobucket.com/albums/k2...ois/orchid.jpg

whats is happening? will it die?

Unfortunately probably.
From what I can see it looks like a Phalaenopsis variety, a Moth orchid, so
do some research on the net about their requirements and how to grow them.
These grow as epiphytes, clinging on trees, with their thick white roots
clinging onto the branches and hanging down into the air.
From that you will realise they need rainwater with little or no mineral
content, they need shade from the strongest sun, they need them and their
roots to dry out quickly between showers, they need weak fertiliser (half
strength at most).
So what have you been doing wrong? Watering with hard tap water, or using a
water tray so the roots stay wet, spraying the plant with water and letting
it sit in the crown, perhaps too much fertiliser, if you had given it too
much light the leaves usually turn red but don't die.

If, as I suspect, it's too much or the wrong water then it will need to be
repotted as the compost will be toxic. So you will need to get some proper
Phalaenopsis compost, usually large pieces of bark and a little
charcoal/peat etc with some moss, and a new pot. Don't get the stuff for
cymbidiums.
Use a spray to water, don't let the water sit in the crown, and do it in the
mornings so the plant has time to dry out before night.
Then give it what it likes and hopefully it will start to regrow roots and
if they grow outside the pot that's OK, just don't let them attach
themselves to anything as you will break them off trying to remove them.

--
Regards
Bob H
17mls W. of London.UK