A backlight module, a display panel and a display device. The backlight module includes a first light transmission substrate arranged on a light-emitting face. A projection of the first light transmission substrate on the light-emitting face coincides with the light-emitting face. A first reflection mirror and a second reflection mirror are also arranged on the first light transmission substrate. The first and second reflection mirrors are spaced apart and facing each other, and the second reflection mirror is arranged in such a way as to enable vertical emergent light on the light-emitting face to be incident to the first reflection mirror after undergoing a total reflection. The first reflection mirror is arranged in such a way as to enable light reflected by the second reflection mirror to exit after undergoing a total reflection. A plurality of light transmission holes are evenly distributed on the second reflection mirror.