Mine mobile capsule demand for refrigeration equipment and Gravity natural circulation were analyzed, refrigeration system used in mine portable capsule was designed, the natural circulation cooling way was adopted, which got Cold from the ice storage box, released cold to the defend space. According to the special working conditions of mine, the actual design, the points for attention during the application were pointed out. The lab study showed that this equipment can maintain protective space average, with temperature 26 ℃, the average humidity 60%, in the external environment of 55 ℃ and 30 ℃, under the condition of rated load of 12 people, achieved the design purpose.