Outdoor large LED display screen unit and LED display screen

The utility model provides an outdoor large LED display screen unit. The display device comprises a plurality of display modules, a power supply module and a shell module, each display module comprises a mask, a circuit board and a bottom shell; the circuit board is mounted on the first side surface of the bottom shell; a plurality of groups of three-primary-color LED lamps are arranged on the circuit board; the shell module comprises a cover plate, a door plate, a hanging ring, a supporting piece and a mounting piece. A first sealing rubber ring is arranged between the first side surface of the cover plate and the second side surface of the bottom shell; a second sealing rubber ring is arranged between the door plate and the second side surface of the cover plate; a plurality of groups ofheat dissipation holes are formed in the door plate; the power module is mounted on the cover plate and electrically connected with the circuit board, the lifting ring is in threaded connection withthe cover plate, the first