Electric vehicle cooling modes are divided into air cooling, liquid cooling and phase change material cooling, the air cooling is divided into natural air cooling and forced air cooling. This paper selects the forced air cooling as the study object, and researches the heat dissipation performance of different airflow duct modes, the results indicated that: as considering that changing the longitudinal battery pack into horizontal battery pack, it could improve the heat dissipation performance by shorting airflow path; it increases the contact area for thermal conduction by adding bottom duct, and the area of battery pack top exists natural convection, so the heat dissipation performance of bottom duct mode is more superior; for battery pack with bottom duct mode, it uses the double “U” type duct instead of double “1” type duct in order to improve the heat dissipation performance; when the heat dissipation condition is poor, it could reduce the SOC state or charge & discharge rate to satisfy the heat dissipation performance requirements; as considering the practical operation condition of battery pack with double “U” type duct, it has a large margin of high charge and discharge rate to meet the needs of electric vehicle acceleration or deceleration operation.