In order to enhance the cooling capacity of the light emitting diode (LED) radiator and reduce the weight of it, a slotted and staggered design is incorporated into the traditional LED sunflower radiator. The three-dimensional model of radiator is built by Solidworks software, and thermal simulation is carried out by Flow Simulation, which is the plug of Solidworks. Using the traditional sunflower radiator as a basic model, the average error between the actual temperature of the four monitoring points and the simulated temperature is 4.6%, which is within the allowable range. This result confirms the correctness of the simulation steps. Then, the influences of number and length of seams on the highest temperature of LED chip are studied, and the results show that the slotted and staggered design effectively enhances the convection cooling performance of the LED radiator. The highest temperature of the LED chip is 122.15 ℃ while the input power is 26 W, the number of seams is 9 and the length of seams is 1 mm. Under the same set of model parameters, the highest temperature of the LED with slotted and staggered radiator is reduced by 8.68 ℃ compared to the one with traditional sunflower radiator, and the weight of radiator is also reduced by 6.85 g. The slotted and staggered design is in favor of delaying the forming of thermal boundary layer and improving distribution of flow field, which enhances the cooling capacity and reduces the weight of sunflower radiator under the nature convection conditions.