At room temperature, the earth’s infrared energy is huge, but it can not be effectively used because of its wide band, low strength and easy to conduct. The earth’s infrared radiation (8～15μm) of the wide bandwidth at room temperature is converted into the water medium at relatively narrow bandwidth (9.56～10.02μm) and stable temperature, the water medium radiate the infrared long-wave outward through the capillary network, and then realize the energy conversion through the long-wave antenna. Results show that the radiation energy and energy density of the capillary network per unit area flowing through the media medium is huge. The parameters of long-wave receiving antenna and antenna array are calculated. Considering the 16 °C water medium, the conversion rate of infrared radiation can reach 94%.