A backlight module, comprising: a back plate comprising a bottom plate , side plates surrounding the bottom plate , and bent parts formed by bending the side plates , wherein the bottom plate , the side plates , and the bent parts form a mounting space , each of sides of the bent parts away from the bottom plate is provided with a limiting step , each of the bent parts comprises an upper step surface and a lower step surface connected to the limiting step , and a part of a side of one of the upper step surfaces is recessed with an accommodating groove adjacent to one corresponding lower step surface ; a support plate detachably disposed in the accommodating groove , and provided with a hanging ear protruding from a part of the support plate adjacent to the limiting step ; a reflective sheet accommodated in the mounting space and disposed on the bottom plate ; a light guide plate accommodated in the mounting space and disposed on a side of the reflective sheet away from the bottom plate ; and a film accommodated in the mounting space , disposed on a side of the light guide plate away from the reflective sheet , and provided with a positioning portion , wherein the positioning portion comprises a positioning plate extending from a part of a side of the film close to the accommodating groove and perpendicular to the film and a positioning step extending from the positioning plate to the accommodating groove and forming an angle with the positioning plate , the positioning step is provided with a positioning hole , and the positioning step is sleeved on the hanging ear through the positioning hole . a back plate comprising a bottom plate , side plates surrounding the bottom plate , and bent parts formed by bending the side plates , wherein the bottom plate , the side plates , and the bent parts form a mounting space , each of sides of the bent parts away from the bottom plate is provided with a limiting step , each of the bent parts comprises an upper step surface and a lower step surface connected to the limiting step , and a part of a side of one of the upper step surfaces is recessed with an accommodating groove adjacent to one corresponding lower step surface ; a support plate detachably disposed in the accommodating groove , and provided with a hanging ear protruding from a part of the support plate adjacent to the limiting step ; a reflective sheet accommodated in the mounting space and disposed on the bottom plate ; a light guide plate accommodated in the mounting space and disposed on a side of the reflective sheet away from the bottom plate ; and a film accommodated in the mounting space , disposed on a side of the light guide plate away from the reflective sheet , and provided with a positioning portion , wherein the positioning portion comprises a positioning plate extending from a part of a side of the film close to the accommodating groove and perpendicular to the film and a positioning step extending from the positioning plate to the accommodating groove and forming an angle with the positioning plate , the positioning step is provided with a positioning hole , and the positioning step is sleeved on the hanging ear through the positioning hole . <EOS>