The floor radiant cooling system has the advantages of good room temperature uniformity, low noise, low operating cost and high comfort, but from the existing research, the contradiction between the cooling capacity and condensation of the floor radiant cooling system greatly affects the promotion and application of the system. By building a floor radiation synergistic tunnel wind cooling test bench based on virtual natural cooling source,the condensation characteristics, cooling characteristics and energy consumption characteristics of floor radiation synergistic tunnel wind system under the two modes of cold water tandem and mixed water from the perspective of cold water cascade utilization was explored, and the energy-saving principle of cold water cascade utilization was analyzed. The results show that the cold water cascade utilization mode can obtain a series water supply of 0.5 m3/h, an air supply volume of 45 m3/h as the optimal working condition, a cooling capacity of 474.3 W and a system energy consumption of 238 W due to the water supply temperature above 12 °C and the absence of condensation in combination with tunnel wind.