Chrome bookmarks are stored in the profile directory for each Chrome user.
Inside the C:\Users\%USERNAME%\AppData\Local\Google\Chrome\User Data\Default directory are two files. Bookmarks, and Bookmarks.bak. One is for your current bookmarks, and the other one (with the .bak extension) signifies that it is a bookmarks backup, if anything goes wrong Bookmarks.bak gets overwritten every time you close Chrome.
If you don’t see the .bak file extension and just see two files named Bookmarks, click Organize menu > select Folder and search options.
In the Folder Options window, click over the View tab and uncheck Hide extensions for known file types option. You’ll now see the previously hidden .bak extension.
To restore the backup, close all open Chrome browser windows. With Chrome closed, rename the Bookmarks file to Bookmarks.old and rename Bookmarks.bak to Bookmarks (You should probably make a copy of both Bookmarks files and put them into another folder before you do any renaming).
You’ll see your bookmarks when you relaunch Chrome.