The invention discloses a switch-over assembly which comprises a fixing device and a connecting part. The fixing device is sleeved with the connecting part. Protruding portions and accommodating portions are arranged between the fixing device and the connecting part and correspond to each other. When the protruding portions and the accommodating portions are connected, the connecting part and the fixing device are fixedly connected. Each protruding portion is located on a supporting face in the corresponding accommodating portion. An elastic element is arranged between each protruding portion and the corresponding supporting face and makes contact with the protruding portion and the supporting face. When gaps are formed between the protruding portions and the supporting faces, the gaps are compensated by the elastic elements. After the technical scheme is adopted, the switch-over assembly is simple in structure, and the mounting and fixing effects are good.