Using the chimney effect to change the air movement around the radiator ,a design structure is proposed,the size of the design structures are optimized and their effects are analyzed.The design and e xperimental structure models of LED are established with SolidWorks.The dynamic dimension of the structure and the surrounding air movement under the optimal heat dissipation performance and optimal comprehensive performance are obtained by engineering fl uid dynamics (EFD) thermal simulation.The experimental results show that the the rmal resistance of the radiator is reduced by 29.4%,and the comprehensive performance can be increased by 43.9% with the introduction and op timization.With the introduction of the chimney effect,the radiator has a significant effect of sucking around the air,and the movement of air out of the radiator changes from moving to the middle to moving upward along the direction of the cylindricity,which enriches the air mov ement around the radiator.