Dry-wet combined closed-loop cooling towers, divided into two parts structurally: the upper part is a finned air cooler, and the lower part is a counter-current closed-loop cooling tower heat exchanger. The upper air cooler can meet the cooling process requirements during winter, while the wet heat exchanger is used in summer to utilize latent heat of vaporization to lower the temperature of the heat medium, thus reducing initial investment and maximizing water conservation.