By default, your contacts are automatically included in the Safe Senders list of the Outlook Junk Email Filter. Messages from safe senders are never moved to the Junk Email folder by the Junk Email Filter.
To change this setting, do the following:
Click the Mail icon, and then click the Home tab.
In the Delete group, click Junk, and then click Junk Email Options.
On the Safe Senders tab, select or clear the Also trust email from my Contacts check box.