Microsoft: Set Internet Explorer ( IE ) Home Page with Group Policy

You can use the steps below to set the IE home page with Group Policy.
1. Create a GPO and link it to a scope (Site, Domain or OU level not group) that contains all your specified user accounts.
2. Edit the GPO: GPO name-->User Configuration-->Policies-->Administrative Templates-->Windows Components-->Internet Explorer-->Disable changing home page settings-->Enable-->Home Page: input your specified home page
3. Logoff or restart user computer to apply this GPO


Reference:
Enforcing an IE default page via GPO
http://social.technet.microsoft.com/Forums/en-US/20061e82-f857-4d38-a494-e8af18a5b51a/enforcing-an-ie-default-page-via-gpo?forum=winserverGP