Hi,
I am a Chinese scholar. I have been in US in 2004 for 4 months with a J1 visa.
And I came back in US in 2006 with a J1 visa. With the US-China treaty, I need not pay any tax in 2006. And I pay my ss & medicare tax in 2007. In June, 2007, we have a newborn daughter. So my question is: can I claim Child credit when I file 1040nr?( I haven't pay the federal and state tax in 2007.)

Thanks.

Qiao

If you are exempt from federal and state taxes (as you have claimed), then you are a nonresident. You don't even pay Social Security and Medicare taxes.
Nonresidents don't get child tax credit. Also, if there is no tax on your return, the child tax credit is of no use to you; it is not a refundable credit.