I bought iphone 4 from other country.and phone is locket and deactivated?

I bought iphone 4 from other country. And phone is locket and deactivated. Can i unlock the phone and then activate with my sim card?

Take it to your carrier they should be able to unlock it and reset it.

Yes, you need to have it iPhone Factory Unlock for you to be able to use it with your carrier. Try to check it with your carrier if they can unlock it for you, if not then I suggest that you get an iPhone Factory Unlock Service.