The present disclosure discloses a modular hardened optical fiber connector and an assembly method thereof. The modular hardened optical fiber connector comprises: a ferrule stub module which comprises a pre-installed optical fiber; an optical cable holding module which comprises an optical drop fiber of an optical drop cable; an optical fiber protection module which is arranged around a connection portion between the pre-installed optical fiber and the optical drop fiber; an inner housing module which accommodates the ferrule stub module, the optical cable holding module and the optical fiber protection module therein; and an outer housing module which accommodates the inner housing module therein.