If you are using the backup feature within Lightroom, your catalog should be backed up to the location that you choose. But the backup should not create duplicate images because the backup in Lightroom doesn't do anything to your images. If you want to backup your images you will have to do that separately and outside of Lightroom. I don't know if this answers your question. If not, please clarify. I apologize that the answer is in English.
Understand it. Do I need backup picture should use third party software correct?
What is the catalogue? why do I need backup catalogue?
The Lightroom catalog is a database. It is a key element to Lightroom functioning properly. The database keeps track of where your images are located as well as all the adjustments that you have made to your images. Changes made to images in Lightroom do not get applied to the image files. They are stored in the catalog. If you want to give someone a copy of an image that includes all of the Lightroom adjustments then you need to export a copy.
Because of the information stored in the catalog, it should be backed up on a regular basis. This interval can be set in the catalog settings. I have mine set to backup weekly. There are other options as well. But backing up the catalog does not Backup your images, and Lightroom provides no utility for that. You need to use other software and other means to ensure that you have backups of your images.
Thank you Jim, I understand.