The present disclosure provides a backlight module and a display device. The backlight module includes a light source and a light guide plate. The backlight module further includes: a light collimation element configured to convert divergent rays emitted from the light source into parallel rays; a polarizing beam-splitting element configured to convert the parallel rays into a first polarized ray and a second polarized ray with their vibration directions perpendicular to each other; and a phase delaying element configured to convert the vibration direction of the second polarized ray to be identical to that of the first polarized ray, so as to form a third polarized ray. The first and third polarized rays form incident polarized rays entering into the light guide plate. The light guide plate is configured to receive the incident polarized rays.