Provided is a corner protection device, comprising a slide rail shaft, a corner protection and detent mechanism, and a corner protector. The slide rail shaft is fixed on the LED display screen cabinet, the corner protection and detent mechanism is fixed on the sidewall at the top of the cabinet, and the corner protector is slidably disposed on the slide rail shaft. When the corner protector slides to the top of the cabinet, the corner protection and detent mechanism can fix the corner protector on the top of the cabinet so as to protect it. Also provided is an LED display screen cabinet, comprising the corner protection device mentioned above, and a support piece arranged on the sidewall of the cabinet. When the corner protector is fixed on the top of the cabinet, the support piece and corner protector can jointly support the display screen cabinet on the support platform.