The invention relates to an outdoor cabinet and a top cover thereof. The outdoor cabinet comprises a cabinet and a top cover arranged above the cabinet. The top cover comprises a top board with an oblique board segment. The oblique board segment is provided with a connecting platform for mounting a suspension ring. The connecting platform has a horizontal mounting surface. A mounting hole for mounting the suspension ring is arranged on the horizontal mounting surface. According to the tope cover of the invention, the connecting platform is arranged on the oblique board segment of the top board; the connecting platform is provided with a horizontal mounting surface; the suspension ring is connected with the top board through the horizontal mounting surface of the connecting platform; not only is pressing of a sealing pad on the top board by the suspension ring facilitated for realizing sealing between the suspension ring and the top board, but also the suspension ring does not generatea shearing force to the top board which is connected with the suspension ring when the suspension ring bears a vertical pulling force, thereby preventing tearing at the connecting part of the suspension ring in a hoisting process.