how can i identify spider hunter wasps from Sphecidae family

[shytonak]

can any body tell me how can i identify spider hunter wasps from Sphecidae family?

[Matt Smith]

You need the Royal Entomolgical Society Handbook for Sphecidae (M C Day, 1988, Vol 6 part 4). This is currently out of print but is in the process of revision.

[oxycera]

I take it you mean from each other in the field.
A bit tricky but experience should suffice eventually. Pompilids usually flit around near the ground in a rather jerky way. They always strike me as behaving in an intelligent manner! - and can be difficult to catch.
I think certain ichneumons are more likely to cause confusion than your typical sphecid.