when i clicked the icon and this windows shows up
"blender" can't be open cause it comes from undefined developer
your security preference allows installation of app only from mac app store and other developers identified.
sorry, i have bad english... but i need help
(the original image of the pop up window) http://flic.kr/p/dtS8kh
Not a mac guy but...
It sounds like your security settings need to be adjusted to allow Blender to run. Maybe this can be done on a per-application basis?
How to do this is maybe a question for a mac forum.
I guess you need to disable the GateKeeper...
or Enable ANYWHERE option from the General Setting of your Mac:
It looks like this...
Allow applications downloaded from:
O Mac App Store
O Mac App Store and identified developers
Blender is a safe App but be aware that you must be cautious when opening other Downloaded Apps.
Blender User, Graphic Artist, Industrial Designer, Photographer, Rocker