Backlight module and liquid crystal display device containing same

A backlight module (10) and a liquid crystal display device (100) containing same. The backlight module (10) comprises a horizontally arranged bottom reflective sheet (4), a frame (2) arranged at an edge of the bottom reflective sheet (4), a side reflective sheet (5) fixedly arranged on the frame (2) and forming a hollow reflective cavity (6) with the bottom reflective sheet (4), a light source (3) fixedly arranged inside the reflective cavity (6), and a transflective film (1) arranged at an opening of the reflective cavity (6), wherein the transflective film (1) is connected to the light source (3) and the side reflective sheet (5) in an overlapped manner. Thus, the backlight module (10) has a light overall weight and low production costs.