A ferrule assembly including: a ferrule formed with a fiber bore for receiving an optical fiber therein; and a rear seat connected to a rear end of the ferrule, wherein the rear seat is formed with a hollow chamber passing through the rear seat in a longitudinal direction and communicated with the fiber bore of the ferrule, and wherein an additional injection hole for injecting an adhesive into the ferrule assembly is formed in an external profile surface of the ferrule assembly, and directly communicated with the fiber bore of the ferrule or the hollow chamber of the rear seat. The ferrule assembly is configured to be adapted to insert a fiber before filling an adhesive and protect the fiber that has been inserted into the ferrule assembly during inserting the fiber or filling the adhesive into the ferrule assembly.