A display device includes a backlight module, and the backlight module includes a light-guiding plate, a light-emitting assembly, and an adhesive member. The light-emitting assembly is disposed correspondingly to the light-guiding plate and includes a substrate and a plurality of light-emitting elements. The substrate includes a first surface, and the first surface includes a component arrangement region and a planar region. A first gap is formed between the planar region and the component arrangement region, and the planar region and the component arrangement region are electrically isolated from each other. The light-emitting elements are disposed on the component arrangement region. The adhesive member connects the light-guiding plate and the planar region. An assembling method of the display device is also provided. This disclosure can improve the non-uniform brightness issue (hotspots) or enhance the optical performance.