Sunny,
VFP won't CHANGE the formset/form classes of an existing form. The templates are only for newly created forms.
You can open the .SCX in the class browser and use it's REDEFINE button to change the form to your class.
>I want to use my own form and formset as my default to replace the original form and formset which are supplied by Vfp. I put down my form's and formset's file names into the Template Classes of Option's Forms tab, and clicked the check boxes. I think when I create a new form, vfp will open myform as a new form But, Vfp hasn't do that. It still open the original for me. When I create a formset, however, Vfp used myformset.