Methylphenyl silicone oil was synthesized from methylphenyl cyclosiloxane mixture and octaphenyl cyclotetrasiloxane mixture with dimethylcyclosiloxane under the condition of basic catalyst. The effects of different kinds of phenyl links and contents on the viscosity, density, refractive index and other properties of methylphenyl silicone oil were studied. The results show that the phenyl mole fraction of methyl phenyl silicone oil synthesized by this method is adjustable in the range of 5% ~ 50%, and the type and content of phenyl chain will directly affect its viscosity, density, refractive index and other indexes. With the increase of phenyl mole fraction, the above three indexes increased correspondingly. The type of phenyl chain will affect the flexibility of silicone oil molecular chain. When phenyl is in the same chain, it will increase the rigidity of the molecular chain. Compared with the methyl phenyl silicone oil synthesized by the mixture of methyl phenyl cyclosiloxane, the viscosity of the methyl phenyl silicone oil synthesized by octaphenyl cyclotetrasiloxane increases more rapidly with the increase of phenyl mole fraction.