Normally my girlfriend have a periods on 3 or 4th on a month but this October month she didn't got and today's morning she had a pregasure test and it showed positive, please suggest me the solution.I'm in much tense please help.

Time to seek a professional opinion.

Solution? You either plan to keep the baby, give it up for adoption, or abort it. You make such plans NOW.
If you need help with decisions, please tell us more, including where in the world you are.

First, I have to ask where you are located and her religious beliefs. The next steps depend on those.

In most areas, your only choice here is to support her in whatever choice SHE makes. In most areas the choice is hers and hers alone. As Joy said the three choices are Abort, Adoption or Parenthood. The first choice is hers alone. She has to decide, based on local laws and religious beliefs, whether to have an abortion or not. You cannot force her to make such a decision. As far as adoption is concerned, You can agree to adoption but you can't force it. Again this has to be her decision. You can stop an adoption but not force it. So the last choice is parenthood. If she decides to keep the child you can be required to pay to support it.

So you have very limited options here. You needed to think of these options before you decided to engage in sexual intercourse.

You may as well relax and wait to see if she is indeed pregnant, or not and then she what she wants to do about it. Waiting is the hard part.

I'm assuming that a pregasure test is a pregnancy test, and it was positive? False positives are very rare, so it's pretty certain that she is indeed pregnant.

There are three options, carrying the baby to term and keeping it. Carrying the baby to term and putting it up for adoption. Abortion.

It's her body, and her decision. Are you serious about this girl? You were serious enough to have sex and get her pregnant, so are you serious enough to stick around when she makes her decision?

If she tested positive, most likely she is pregnant, so she needs to go to the doctor and confirm this.

Then as noted, depending on religious and social cultures the choices of keeping the baby, adoption, allowing other family member raise child, or abortion are all options.

Also what ages, if you are both young, you both will need to tell your parents.