according to this topic:Bounding Box Attachment supporthttp://zh.esotericsoftware.com/forum/viewtopic.php?f=7&t=4218,I got something wrong to show the bounding box in unity。
1.First,In the spine editor,I create two bounding box:

2.Import to unity editor,this two bounding box showed in Inspecotor panel.

3.I did two step like the tutorial


4.And there is the question,The bounding box is gray/unavailable.

Don't know why,whitch step I did wrong?
:o :o :o enen
Solved by video of @Mitch in http://zh.esotericsoftware.com/forum/viewtopic.php?f=7&t=4218.
Use the BoundingBoxFollower script.
Let me try more,see why first way is not available.