NOVELTY - Preparing organosilicon electronic pouring sealant comprises: (1) adding olefin-based silane and silicone compound into organic solvent A and then adding catalyst, and removing the organic solvent A; (2) dissolving sulfhydryl compound in organic solvent B to obtain sulfhydryl compound solution, dissolving an olefin-based silane coupling agent in the organic solvent B to obtain coupling agent solution, and removing the organic solvent B to obtain mercaptosilane oligomer precursor; and (3) mixing the olefin-based silane oligomer precursor with the mercaptosilane oligomer precursor.    USE - The method is useful for preparing organosilicon electronic pouring sealant, which is useful for packaging chip, LED or solar battery in vehicle electronic industry and household electronic product (claimed).    ADVANTAGE - The method is capable of simply and economically preparing the organosilicon electronic pouring sealant with high refractive index, reduced energy consumption and improved light transmittance and mechanical performance.    DETAILED DESCRIPTION - Preparing organosilicon electronic pouring sealant comprises (1) adding olefin-based silane and silicone compound to organic solvent A and then adding catalyst, heating the solution at a temperature of 50-100 degrees C and then reacting for 3-12 hours, and removing the organic solvent A to obtain olefin-based silane oligomer precursor, (2) dissolving sulfhydryl compound to organic solvent B to obtain sulfhydryl compound solution, dissolving an olefin based silane coupling agent in organic solvent B to obtain olefin-based silane coupling agent solution, heating the sulfhydryl compound solution at a temperature of 50-100 degrees C, dripping the olefin-based silane coupling agent solution into the sulfhydryl compound solution and then reacting at 50-100 degrees C for 8-48 hours, and removing the organic solvent B to obtain mercaptosilane oligomer precursor, and (3) mixing the olefin-based silane oligomer precursor with the mercaptosilane oligomer precursor to obtain organosilicone electronic pouring sealant.