The invention discloses conductive ink based on a graphene composite material and a preparation method thereof. The conductive ink is prepared from the following components in parts by mass: 1-30 parts of a functional graphene composite material, 1-70 parts of a resin coupling agent, 5-60 parts of a solvent and 1-40 parts of an auxiliary. According to the method, graphene is modified into a functional graphene composite material, low density and high conductivity of graphene can be maintained, the situation that graphene is easily agglomerated and difficult to disperse can be improved, and then affinity between conductive filler and a resin connecting material is improved, so that the high-conductivity conductive ink under a low-content conductive agent can be successfully prepared. The conductive ink is simple in preparation method, stable in system, good in conductivity and easy to print, has a flexible and abrasion-resistance membrane layer, can be widely applied to radio frequency tags, intelligent package, film switches, conductive circuits, sensors and other light flexible electronic products, and has a huge market prospect.