A backlight module is disclosed. The backlight module includes a reflection sheet including a first body and a second body; a light guide plate disposed on the first body of the reflection sheet; an optical film set disposed on the light guide plate; a plastic frame inside of which the reflection sheet, the light guide plate, and the optical film set are all disposed; and a connecting member configured to fixedly bond the second body to an inner side surface of the plastic frame. The present invention can ensure that the reflection sheet is fixedly bonded on the plastic frame well so that not only can a narrow frame design be achieved, but also the optical films can meet the requirement of fixing strength.