A car cover assembly, having a base, a cover body, a cap and a storage body for the cover body; the base is removably mounted onto a car surface; the cap is removably or fixedly connected to the base; the cover body and the storage body are pressed between the base and the cap; the base and the cap clamp and fix the cover body and the storage body; after the cover body is completely folded, it is stored inside the storage body. The car cover assembly can be placed at anywhere on the car for use. A method of using the car cover is also provided.