Abstract: This paper studies the fluid-induced vibration-heat transfer coupling characteristics of a single circular tube with constant temperature, and the variation rules of the cylinder vibration response, temperature field, average Nusselt number and maximum local Nusselt number are analyzed. The results show that when Reynolds number Re=100, mass ratio mr=1.37, and reduced velocity Ur=5, the cylinder vibrates in a clockwise "8" shape, and the transverse amplitude is much larger than the downstream amplitude. The vortex shedding mode is 2S, and the vortex shedding will cause the local Nusselt number to increase abruptly near the rear stagnation point. In this study, the Nusselt number of the vibrating cylinder was significantly larger than that of the fixed cylinder, and the average Nusselt number increased by 5.73%.