I am on h1b visa and my wife is on h4 visa. I am working but my wife does not. My child goes to preschool. Can I claim preschool fees as child care expenses? I read that both should have earned income or if one has earned income the other should be actively looking for work.

Thanks

Both spouses need to have earned income (or be a full time student or disabled), otherwise you don't qualify for the credit.
The part about "actively looking for work" refers to expenses that could be claimed in case the income requirement is met (I would also question how much you can actively look for work if you don't have a work authorization).

I thought I answered this one; must be a redundant posting.

TaxForAliens has it right, except for the attending school exception.

If your wife attends school with at least half-time status, you can claim the daycare credit even though she has NO income.