The present invention discloses a backlight module and LCD module, the backlight module comprises a back cover, a positioning assembly and a backlight assembly, wherein the backlight assembly is connected with the back cover by the positioning assembly, the positioning assembly comprises a positioning component located at the corner of the back cover and a bending portion provided on the back cover. By means of the bending portion on the back cover, the light guide plate and optical films can be fixed easily and expediently, especially for the assembling and reworking of module. In addition, the other parts disposed close to the light guide plate, for example LED, can be protected effectively from being crushed because of the expansion of light guide plate.