The invention relates to a method for preparing an alcohol permselective silicon rubber composite membrane, comprising the following steps of: firstly preparing a PVDF (polyvinylidene fluoride) porous base membrane, dissolving PVDF in an organic solvent to prepare a PVDF solution, stirring to be uniform, filtering, defoaming, wiping a membrane on a polyester non-woven fabric, carrying out a gel bath with water, obtaining a non-woven fabric supported PVDF porous base membrane by adopting an immersion sedimentation phase inversion method, and drying in the air after solution exchange is complete; then preparing a silicon rubber membrane solution, namely mixing liquid silicon rubber containing vinyl, silicon oil containing hydrogen, MQ silicon resins, a chloroplatinic acid solution, nano silicon dioxide and a solvent, stirring to be uniform, filtering and defoaming; and finally preparing the silicon rubber composite membrane, namely coating the membrane solution on the PVDF porous supported base membrane, and carrying out deep crosslinking to obtain an addition-type silicon rubber composite membrane. The composite membrane provided by the invention breaks through the optimal separating property of the traditional pure silicon rubber membrane, has an excellent pervaporation alcohol permselective effect and also has a large-scale industrial application prospect.