The invention relates to the field of drilling fluid, and discloses a high-plugging-performance drilling fluid composition and a preparation method and application thereof. The high-plugging-performance drilling fluid composition contains water, bentonite, Na2CO3, a shale inhibitor, a filtrate loss reducer, a viscosity reducer, an anti-collapse agent, a nanometer plugging agent, a lubricant and aweighting agent, wherein the shale inhibitor is modified asphalt GLA, the anti-collapse agent is calcium carbonate superfine powder C80, and the nanometer plugging agent is nanometer graphene subjected to surface modification by polyethylene glycol. According to the high-plugging-performance drilling fluid composition, the modified asphalt GLA as the shale inhibitor, the calcium carbonate superfine powder C80 as the anti-collapse agent and the nanometer plugging agent are adopted for effectively plugging micro-nano cracks of the shale stratum of the large-displacement horizontal segment of a deep well, a drilling fluid phase is prevented from entering the cracks, the lasting and compact plugging barrier is formed near the well wall, and therefore pore pressure transmission is further prevented, the wedge effect of waterpower is further reduced, the block shedding phenomenon is avoided, collapsing of the stratum is effectively prevented, and the stratum is kept stable.