The invention discloses a straight down type backlight module which comprises a reflector sheet, a diffusion plate, a plurality of light sources and a plurality of supports, wherein the plurality of light sources are located on the side, facing towards the diffusion plate, of the reflector sheet. Each support is installed on the reflector sheet, the top of each support abuts against the diffusion plate, and each support comprises a support body and a plurality of micro interface processing structures located on lateral faces of the support body, wherein each micro interface processing structure is provided with a micro interface facing towards a corresponding support body base seat, and the angle degree of an included angle between each micro interface and a bottom face of the corresponding support body seat and along the direction departing from the corresponding support main body is 0-90 degrees. The invention further discloses a display device provided with the straight down type backlight module. The straight down type backlight module can improve the density of light rays on a top area of each support, relieve support shadows formed on the diffusion plate in a light-on state, and improve the display quality of the display device.