The invention provides a vacuum fresh-keeping outer cover. The top of an upper cover body is connected with an air suction/release device; the periphery of the upper edge of the upper cover body is connected with a flexible cushion body which can be pressed on any horizontal surface; the inside of the upper cover body forms an article receiving space; when a value of air pressure of the article receiving space tends to be larger, the air suction/release device is started up to continuously exhaust air in the article receiving space in order that the article receiving space is always kept in anegative pressure state tending to vacuum so as to keep articles or foods fresh; when a contact compression component of the air suction/release device is drawn upwards, the air suction/release devicecan release air pressure of the article receiving space, and the upper cover body can be rapidly take up so as to be convenient for a consumer to use; simultaneously, the air suction/release can be conveniently separated outside the upper cover body; therefore, the upper cover body is convenient to clean by water.