Abstract: Three kinds of silicone gels with different crosslinking densities were prepared by silicon oxide,homemade low hydrogen containing silicon oil and three vinyl silicon oils with different vinyl contents which synthesized using octamethyl-cyclotetrasiloxane and divinyl-tetramethyl-disiloxane as the main raw materials.The structure of vinyl silicon oil and the properties of silica gels after curing were characterized by ¹H-NMR、FT-IR、TGA、SEM and universal mechanical tester.The test results showed that the structure of vinyl silica gel accorded with molecule design;The thermal stability of silicon gels was related to the crosslinking densities and the Si-O bond content;With the increase of crosslinking density of silicon gels,the tensile strength increased and the elongation at break decreased at the macro level.The number of silicon oxide in the crosslinking area decreased but the size increased at micro level.