Dry-wet combined closed-loop cooling towers, divided into two parts structurally: the upper section is a finned air cooler, and the lower section is a counter-current closed-loop cooling tower heat exchanger. The upper air cooler can meet the cooling process requirements during winter. In summer, a wet heat exchanger is used to take advantage of the latent heat of vaporization to lower the temperature of the heat medium, which not only reduces the initial investment but also maximizes water resource conservation.