The present invention provides a PCB Fixing Mechanism and Liquid Crystal Display Device. The PCB fixing mechanism utilizes annular conducting foam (30) and conductive adhesive (20) to fix PCB (50) on the back plate (10), then improve the contact efficiency between PCB (50) and back plate (10). In cooperate with compressing annular conducting foam by PCB hood (40), the annular conducting foam obtain great conductivity with sufficient compress ratio ensured, further improve PCB grounding, thus can promptly and effectively bypass ESD interference to prevent electrostatic damage. By the way, PCB fixing procedure is simplified and labor hours are saved. The liquid crystal display device using aforesaid PCB fixing mechanism, can simplify PCB fixing procedure, save labor hours, improve PCB grounding and prevent electrostatic damage.