While integrating the apache and the subversion, we are using mod_dav_svn.so and loading this module, can any one help me to know the use of this module?
Roughly speaking, it's a module which allows Apache HTTP Server to serve SVN repositories.
See WebDAV FAQ: "What is mod_dav_svn and mod_dav_fs?"
mod_dav_svn is an interface for mod_dav that provides a CVS like repository which is based on the new Delta-V specification. It is an extension to WebDAV and useful if you need versioning control.