The present invention provides a back frame of flat panel display device, which includes at least two primary assembling pieces. The at least two primary assembling pieces are joined to for a main frame structure of the back frame. The at least two primary assembling pieces includes a primary assembling piece that has a heat source arranged thereon. The primary assembling piece that has the heat source arranged thereon has a first heat transfer capability. The remaining one or more primary assembling pieces of the at least two primary assembling pieces that have no heat source arranged thereon have a second heat transfer capability. The first heat transfer capability is greater than the second heat transfer capability. The present invention also provides a method for manufacturing a back frame of flat panel display device and a backlight system. The back frame, the method for manufacturing back frame, and the back frame of the backlight system of the present invention has a simple back frame structure and can reduce the expenditure of the back frame mold, and can also save the material used for back frame so as to lower down the cost of flat panel display device.