Not sure what you are asking/trying to do but just on the face of your question, sans any further information, the answer is - No!
Workarounds? Depends on what you are trying to do.
Just 1 catalog for 2 different sources of files - No.
You would need to do some manual work. If you duplicate the catalog file (.lrcat) you could rename it and then launch it in Lightroom as a separate catalog.
You would then need to point to the folders on the other drive. See Part 2 at the link below on how to update folder locations.
Need help in solving this issue.
I have 2 external hard drives, of which contain the same images, is there a way that the back up can use the same catalogue as the original?
This is a poor idea. The whole purpose of backups is to protect yourself against some unexpected loss of the original files. The backups should sit there, untouched and unused, forever and ever, except in that unfortunate situation where the original files are lost somehow. By not using the files, you have the highest likelihood that the files will be available in the case of the originals being lost. Use your originals only, don't even contemplate using the backups for anything other than the emergency situation where the originals are lost.
Furthermore, if you start using the backups at some time, and the originals at other times, then you have two sets of files that might not agree with one another, thereby making their value as backups somewhat less that the untouched backups that I described in the previous paragraph.
Do not go down this path!
Thanks for this tip everyone! appreciate It