A side-type backlight module includes a light guide plate and a reverse prism sheet that are stacked. The reverse prism sheet includes a first prism. A surface of the first prism proximate to the light guide plate includes a plurality of prism structures substantially parallel to each other. Each prism structure protrudes toward a direction approaching the light guide plate. A surface of the light guide plate proximate to the reverse prism sheet includes a plurality of strip-shaped microstructures substantially parallel to each other. Each strip-shaped microstructure protrudes toward a direction approaching the reverse prism sheet. An extending direction of the prism structure crosses an extending direction of the strip-shaped microstructure.