The utility model discloses an LED (light-emitting diode) display module and an LED display screen assembled thereby. The LED display module comprises a bottom shell, a lamp panel and a mask, wherein the lamp panel is arranged between the bottom shell and the mask; the bottom shell, the lamp panel and the mask are fixed with each other by fixing pieces; a groove-shaped through hole array is arranged at the corresponding position among the bottom shell, the lamp panel and the mask; the lamp panel comprises a drive circuit board and an LED lamp which is arranged on the drive circuit board; one surface of the lamp board which is provided with the LED lamp is faced to the mask; and the position of the mask which corresponds to the LED lamp can permeate light. In the module, groove-shaped through holes are arranged in the corresponding position among the bottom shell, the lamp panel and the mask and form into the through hole array, so that the groove-shaped through hole array is formed on the whole module, therefore, the ventilating performance of the module is greatly improved, and more heat energy can be taken away by flowing air under the condition that the ventilating performance is improved, so that the heat dissipation problem is solved. The weight of a hollow part and the weight of a heat dissipating device are eliminated from the whole module, so that the weight of the whole module is greatly reduced.