Install sublimetext-insertdate with Package Control or directly install with git clone.

ctrl+` open sublime console and type

sublime.packages_path() to show the packages_path

cd PATH_OF_YOUR_SUBLIME_PACKAGES and git clone

git clone git://github.com/FichteFoll/sublimetext-insertdate.git

then modify Key Bindings-User,add

{ "keys": ["ctrl+d"],"command": "insert_date","args": {"format": "%Y-%m-%d %H:%M:%S"} }

Any time you want insert date,just ctrl+d.will output

2013-05-29 08:30:54