Based on the trapezoidal fin, a new type of plate-fin radiator with a new shape fin is proposed to optimize the heat dissipation. Based on a commercial software COMSOL Multiphysics 6.0， a heat sink model with slots between trapezoidal fins is established. The performance of different slot widths, slot heights and slot moving positions were evaluated, and the influence of fluid velocity on the heat dissipation of different fins was analyzed. The results show that the grooving between trapezoidal fins has a lower chip temperature than that without grooving, and the change of slotting width, slotting height and slotting moving position have an effect on the heat dissipation. At low fluid velocity, increasing the width and height of the slot or moving the slot down can effectively improve the heat dissipation efficiency of the radiator. The heat transfer rate of the optimized trapezoidal slotted fin radiator is 12% higher than that of the original trapezoidal radiator and 22% higher than that of the original rectangular straight fin radiator. The research results can provide reference for future research on the improvement of heat dissipation efficiency of plate-fin radiator.