Silicone oil is a polysiloxane with chain structure of different polymerization degree. It is prepared by hydrolyzing dimethyldichlorosilane with water to obtain the primary polycondensation ring body, and then the ring body is cracked and distilled to obtain the low chemicalbook ring body. Then, the ring body, capping agent and catalyst are put together to obtain a mixture of various polymerization degrees. Silicone oil can be obtained by removing low boiling points through vacuum distillation.