Evaluating indicator for temperature distributions homogeneity was developed through optimization using orthogonal experiment. The influences of rotation speed of air refrigerating machine fan, porosity of flow equalization board and vertical space between frames on temperature distribution were analyzed. The simulation results show that the higher the fan rotation speed is, the better the temperature distribution homogeneity is, although the highest temperature in carriage is basically unchanged; the smaller the porosity is, the better temperature distribution homogeneity is; and the highest temperature in carriage is lowest when the porosity is 0.1; the smaller the frame vertical spacing is, the lower the highest temperature in carriage is and the better temperature distributions homogeneity is. For the “peak area” in temperature distribution, the carriage structure was new designed based on field-coordination principle and the temperature distributions homogeneity can be controlled by adjusting the gas curtain fan’s direction in right air-returning outlet.