how can i access the content of toolwindow "RUN"

You can use RunContentListener to get the console contents.
Register using ExecutionManager.getInstance(project).getContentManager().addRunContentListener()

thanks
but how to use this?
addRunContentListener has a  parameter :

void addRunContentListener(RunContentListener listener)

but how can I create a RunContentListener?

is there any example?

Just create a class implementing the interface
There is no clean API for what you get in the descriptor AFAIK - you will need to use the impl classes that are not documented and can change frequently.

MAybe someone from JetBrains can post a better solution ;-)

oh , i see , i will try , thank you

it seems no api for getting information of the "RUN"  

RunContentDescriptor is so common