The present invention discloses a backlight module, comprising a backsheet, and a light guide plate and a middle frame provided on the backsheet; the backsheet being assembled with multiple spacers, one side of the spacer being connected with the side wall of the backsheet, the opposite side thereof being tightly connected with the light guide plate, on the spacer further being provided with a holding groove; a slot connected to the holding groove being provided corresponding to each spacer on the side wall of the backsheet; the middle frame comprising a vertical supporting portion, the vertical supporting portion comprising multiple intertongue, each intertongue corresponding to each holding groove, on the side wall of the intertongue being provided with a hook; the middle frame being assembled in the holding groove through the intertongue, the hook and the slot being engaged with each other. The present invention further discloses a liquid crystal display device comprising the backlight module.