Demolding device for prefabricated part and use method of demolding device

The invention relates to a demolding device for a prefabricated part, which comprises a barrel, a demolding device and a demolding device, and an accommodating space capable of accommodating a mold is formed in the barrel; the supporting mechanism is arranged on the cylinder body and is used for positioning the mold; the rotating mechanism is arranged on the cylinder body in a sliding manner, and the rotating mechanism can horizontally slide relative to the cylinder body; the cutting mechanism is fixedly connected with the rotating mechanism, the cutting mechanism is provided with a cutting wire capable of moving up and down to be adjusted, the cutting wire can be attached to the inner side face of a mold, and therefore when the cutting wire moves up and down to be adjusted, the cutting wire is matched with back-and-forth rotation of the rotating mechanism to cut and separate a prefabricated part from the mold, and the mold is supported through the supporting mechanism. Concrete is poured into the pouring spa