Abstract: The thermal performance of a Ku-band space traveling wave tube collector was simulated using the finite element method, attaining the temperature distribution of the collector. The influences of contact resistance and heat radiation on the thermal performance were analyzed and compared. The results show that the contact resistance obviously hinders the heat dissipation so that the temperature of the whole collector raises and the highest temperature increases about 13 ℃; the heat radiation reduces the temperature at the same time and the highest temperature falls about 5.2 ℃, leading to a more uniform temperature distribution. The heat-stress coupled analysis was done using an indirect method, gaining the displacement distribution contour map of the collector. It is shown that the struct