Thanks Anubha,
I have read this Hide/disable the attach to email/share files
my version is adobe reader XI, I cannot find a key about "send file as email attachment" in my regitry HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\11.0\AVGeneral\cCommonToolsDesktop
and also no "cServices" or "bEnableShareFile" in HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Adobe\Acrobat Reader\11.0\FeatureLockDown
is that because there are some differencts between 2 version?