In order to meet the best performance requirements of the power battery and ensure the safe operation of the battery system, effective thermal management design is necessary for most of battery systems. By using CFD simulation technology, three kinds of whole module heat dissipation modes natural heat dissipation,single layer watercooled plate heat dissipation and doublelayer watercooled plate heat dissipation,were analyzed;the influence of the doublelayer watercooled plate inlet water flow rate on the heat dissipation effect of the battery pack was studied.The results show that the temperature rise and temperature difference of doublelayer watercooled plate heat dissipation is relatively small,and the heat dissipation effect is more obvious;when the water flow rate is less than 5 L/min,the overall temperature of the module decreases obviously with the increase of the water flow rate;when the water flow is greater than 5 L/min,the overall temperature of the module decreases slowly,and the heat dissipation effect is not obvious.