Hello Jinlong,
As Tim already mentioned, the first step to have your scenario working is to ensure that both domains __trust each other__. This is a must.
Additionally to that, if I correctly understood, you're using SAP Netweaver Single Sign-On 2.0 product as your SNC product to achieve this, correct? In that case, you can follow the SAP NWSSO2.0 guide, section 3.5.2.1.5 - Using Kerberos for SNC with Users in Different Domains. There are some minor particularities in your setup so your SAP can recognize both domains, explained in the guide.
At last, the SAP NWSSO2.0 guide can be found under: http://help.sap.com/nwsso
I hope this helps.
Best Regards,
Guilherme de Oliveira