how to do intervlan routing between two hosts in different subnet separated by two layer 3 switches & without using ip routing command & by using the concept of native vlan.
Since there is no common layer 2 connection between distinct VLANs they need to communicate through a layer 3 device - a router. If you don't want your L3 switches to route you require an additional router.
The native VLAN (of a trunk port) is the VLAN untagged traffic is associated with. This is unrelated to routing.
Edit: for a more specific answer you'll need to provide a more specific question: provide a network diagram, switch models, switch configurations and I'll update the answer.