回复：EAD H1 ?

my I485 get denied for some reason (very unlikely), what is the worst result?
You will be out of status immediately.
Can I appeal on I485 and continue use the EAD?
It is based on which notice you get. If it is denied, you can not use EAD.

Is my approved I-140 still valid, so I can file another I485 later?
Yes. But you are out of status in America, so you will not get chance to do it in America.
Any thoughts on this, Xiaobaitu or other experts? IS there a time frame for approved I-140? or once it's approved, it will be valid for ever as long as my working field not changed.
I am not sure. But I do not think it is forever.