The invention relates to a preparation method of a double-enzyme glucose sensor based on graphene and belongs to the technical field of material preparation. The method comprises the following steps: adopting ionic liquid to functionally modify the dispersibility of graphene, combining the modified graphene with platinum nono-particles to promote electron transfer, using a layer and layer self-assembly method to decorate the graphene onto a glassy carbon electrode, utilizing a biological signal sensitization amplification effect, combining with glucose oxidase and horseradish peroxidase, drying the substances for 24 hours at 4 DEG C, so as to enable the electrode surface to form a layer of uniform composite membrane, and preparing the double-enzyme glucose sensor which is used for quick electrochemical gauging of glucose. The nanocomposite prepared by the preparation method is good in biocompatibility, low in cost, simple and quick, and utilizes the stationarity of bio-enzymes. The biosensor prepared by the preparation method is high in sensitivity, good in stability, wide in linear range, has certain antijamming capability, and can be widely applied to diabetes diagnosis and food technical monitoring.