I came to US on finace visa and got married..we filed for work permit and for adjustment of status...and will be receiving my EAD very soon.

i want to ask for how long this EAD will be valid??

One year is the standard issue. Some offices will vary.

thanks.

what will happen after one year?
what will i have to do??
will i have to do another interview?

What is your local office? In most cases, the AOS interview will occur before the EAD has expired. If not, you can apply for another EAD after the first one expires.

There is no interview for an EAD. You just show up at the local office and they take your photo and fingerprint you.

so you mean if i have green card i do not need EAD???
After interview how much time it takes to get green card???

Once you have your green card you never need an EAD ever again. Usually, your passport is stamped at the AOS interview. Once approved, you are free to work to your heart's content. The green card should arrive several weeks later in the mail.