Q: Can iphone 5s restore back to iphone 4?

Howdy KrizChieh,

Thanks for using the Apple Support Communities.

I see you'd like to restore from a backup of another iPhone.  As long as the iPhone's backup is from the same and/or older iOS version than the iPhone it's being restored to, then you will be able to restore from that backup.  For more information please take a look at the links below.

If you need help restoring your device from an iCloud backup

If restoring from an iTunes or iCloud backup requires a newer version of iOS

Take care.