The invention relates to the field of power generation equipment, and discloses a cooling device of an indirect cooling tower, a circulating water cooling assembly and a power generation system. The cooling device comprises a water collecting component, an annular pipeline and a plurality of cooling pipes, wherein the water collecting component and the annular pipeline are arranged at an intervalin a vertical direction, both ends of the plurality of cooling pipes are respectively connected to the water collecting component and the annular pipeline, the plurality of cooling pipes are circumferentially arranged on the annular pipeline at intervals and are gathered towards the water collecting component so as to form a conical structure, a water inlet is formed in the top end of the coolingdevice, and a water outlet is formed in the bottom end of the cooling device. According to the cooling device of the indirect cooling tower, the circulating water cooling assembly and the power generation system, the heat exchange area of the cooling device and air vertically extends so as to form long heat exchange flow, the effective heat exchange area is increased, and the flow resistance of the air in the vertical direction is low, so that a good air dynamic field can be formed to cool, the cooling efficiency is obviously improved, the occupied area of the cooling tower is reduced, and theproduction cost is reduced.