when we make subinterfaces on Router Example(fa0/0.1) this subinterface work on which OSI Layer.
To go back to Kiran's original question about which OSI layers works on virutal interfaces, a virtual interface such as an Ethernet subinterface works at all the same OSI layers that a physical interface works at.
So certainly it works at layers 2 and 3 as already mentioned. And to the extent that it might be the source or destination of TCP based traffic such as telnet we could say that it works at layer 4. And to the extent that it might be the source or destination of things like SNMP we might say that it works at all the way up to the application layer.