The invention discloses a self-adjusting street lamp shade. The self-adjusting street lamp shade comprises a shade body, wherein a luminous body is installed in the shade body, the shade body comprises a shade top and a plurality of louvre blades, the louvre blades are connected by connecting lines, inner connecting lines are arranged on one side, which faces towards the luminous body, of the louvre blades, the top ends of the inner connecting lines are fixed to the shade top, electromagnets are arranged in fixed positions of the inner connecting lines and the shade top, the electromagnets are electrically connected with a rain sensor, the rain sensor is located above the shade top, and an iron block is arranged on the inner connecting line located above the uppermost louvre blade. When rainwater is sensed by the rain sensor, the electromagnets are powered on, the iron block is absorbed by the electromagnets, the inner connecting lines are pulled to lift, the louvre blades are pulled to move upwards towards the luminous body, the louvre blades are vertical, and the close ends of the louvre blades are tightly abutted; when rainwater is not sensed by the rain sensor, the electromagnets are powered off, the iron block naturally falls, the inner connecting lines descend, and the louvre blades are pulled to be horizontal by the inner connecting lines. According to the self-adjusting street lamp shade, when the louvre blades are horizontal, the circumference of the shade body is ventilated, and when the louvre blades are vertical, rainwater is shielded.