If I only have income on our joint federal tax return will they intercept it because my husband owes back child support

They will if you do not take steps to avoid the problem.

You do that by submitting Form 8379 as an Injured Spouse, and properly allocate your refund between you and your husband. If you do that correctly, they will only take HIS part of the refund.

If you believe that you will need professional help filing this year, this IS what I do. Please double-click on my name (Atlanta Tax Expert) above to access my profile. You will find my email address in the signature portion of the profile (scroll down to the BOTTOM of the page).