Click the Bookmarks button
and select Show All Bookmarks to open the Library window.
From the toolbar on the Library window, click Import and Backup and choose Export Bookmarks to HTML....
In the Export Bookmarks File window that opens, choose a location to save the file, which is named bookmarks.html by default. The desktop is usually a good spot, but any place that is easy to remember will work.
Click the Save button. The Export Bookmarks File window will close.
Close the Library window.
Your bookmarks are successfully exported from Firefox, to import them into Safari proceed to the next section.
Importing bookmarks into Safari
On the menu bar, click on the File menu and choose Import Bookmarks....
Find the file you saved from Firefox and click Import.
At the top of the Safari window, click on the File menu and choose Import Bookmarks....
If you don't see the menu bar, press the Alt key.
Find the file you saved from Firefox and click Open.
Name the Bookmark folder whatever you would like.
Click on the Bookmarks menu to ensure all of your bookmarks have been successfully imported.