Magento Dashboard show blank page only header and footer show, And same as cache management page show blank.
what is the issue how to solve this.
Normally this happens when you have created a new admin page and not properly configured a layout handle for this.
I would suggest that you download a copy of the version of magento that you are using and do a diff compare between your site and the adminhtml theme to identify where there are changes.
Failing that (if there are no changes), disable your modules and you will likely find that one or more custom modules has interfered with it - disabling and re-enabling them until you isolate which one it is then you can debug the module.