A center pillar reinforcement unit for a vehicle may include: a plurality of reinforcement beams disposed on an exterior circumference of a center pillar inner panel in a height direction; an upper bracket disposed on an upper end portion of the center pillar inner panel and a roof rail, and fixing an end portion of the plurality of reinforcement beams; a center bracket disposed on a center portion of the center pillar inner panel, and fixing a center of the plurality of reinforcement beams; a lower bracket disposed on a lower portion of the center pillar inner panel, and fixing a lower portion of the plurality of reinforcement beams; and a gusset bracket formed inside of a side sill seal so that the lower portion of the plurality of reinforcement beams is assembled.