The invention relates to a regulator brush holder of an automobile alternating-current generator, which comprises a regulator unit, a shell, a plug element, a sliding brush and radiating fins, wherein a cavity for holding the regulator unit and a guide region for holding the sliding brush are arranged in the shell, the plug element is arranged at the upper end of the shell, and the radiating finsare arranged at the lower end of the shell. The invention has the advantages of simple structure, good heat radiation effect and easy operation. Besides, damage on the cooling body can not be prevented in the installation and debugging process, the cooling body has big cooling area, and the regulator structure unit has the uniform and reliable cooling effect in the vertical direction.