my itunes coudnot update my iphone

You should visit an Authorized Apple Service Provider next to your place and ask them to diagnose your iPhone.

Seems this issue is hardware related.

Use this link to find one:

Apple - Find Locations

Does the iPhone start up normally if you force restart it?

Force restart iPhone - Apple Support

Are you using the original Apple USB cable that came with the iPhone?

Can you try to connect to another computer?