In order to understand the effects of the soil-air heat exchanger on the surrounding soil and roots of a double-film solar greenhouse, a new double-film solar greenhouse and a single-film conventional greenhouse was compared in Lanzhou. The results show that heat exchanger affects soil temperature on cloudy days. On sunny days, soil temperature is greatly influenced by solar radiation. The shallow soil temperature of the double-film solar greenhouse is higher than that of the single-film conventional greenhouse, and the fluctuation range of soil surface temperature of single-film conventional greenhouse is obviously stronger than that of the double-film solar greenhouse. Double-film solar greenhouse can effectively increase the soil temperature, and the indoor thermal environment stability of the double-film greenhouse is stronger than that of the single-film greenhouse.