Is it possible to split by using sewing operation in CATIA V5?

Sew surface command performs a boolean operation by combining a surface with solid body. If the surface boundary entirely lies on the solid you can sew using the surface boundary projection on to the solid.

So the answer for your question is it possible to split by using sewing operation in Catia V5-

Yes provided if the part has got both Surface and solid body as I mentioned above. It is not possible to split using sewing operation between two solid bodies. It should contain atleast one surface body then only split will be possible by sewing.