A covering structure of a mixer includes: a fixed ring connected to the head of a mixer; an upper ring; and a lower ring. The fixed ring is further surrounded by a protruding ring. The upper ring has a striding part on its inner wall to stride on the protruding ring. The upper ring further has at least two stopping parts at an interval. A concave part is formed between each pair of consecutive stopping parts. One end of the lower ring is formed with connecting parts whose number is the same as that of the stopping parts. Its other end is connected downward with a covering element. The connecting parts of the lower ring are inserted via the concave parts on the upper ring and above them. By rotating the lower ring, the connecting parts urge against the stopping parts to form a rotating ring that can rotate along the protruding ring.