A liquid crystal display (LCD) device and a fixing device thereof are disclosed. The LCD device comprises a light source, a light guide plate and an LCD panel. The fixing device comprises a side plate, a top plate perpendicularly extending from an upper end of the side plate, a partition plate perpendicularly extending from a middle portion of the side plate, and an abutting plate perpendicularly extending from a lower end of the side plate. The partition plate, the top plate and the side plate form a first snap-fit groove for receiving the LCD panel. The partition plate, the abutting plate and the side plate form a second snap-fit groove for receiving the light source. A lower end of the abutting plate is further connected with a supporting portion for supporting the light guide plate, and a partition is formed between the supporting portion and the abutting plate.