hello all,
I cant bake this object proper. what might be problem. anyone can help? I am not very good at this, kind of new and my english not good also 
Your object has a negative scale so in effect it’s inside out, therefore the ambient occlusion is just black
Apply the object scale with Ctrl+A and then bake.
Your UVs are only talking up about a third of the UV space ! Why is this, use the all the space you have available
thank you very much