Hi Xiang,
Thanks for using Syncfusion products. The GridDataControl has different record types that could be customized easily with the IGridDataVisualStyle interface, One more way is to use the Model.QueryBaseStyles event and then add the Font to the BaseStyles,
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=sample1654137649.zipPlease check the above sample.
Thanks,
Fahad