This study mainly establishes the heat transfer finite element analysis model of high-energy fiber lasers during rotational movement. The temperature field simulation of AISI 1045 (medium carbon steel) is carried out. With the establishment of this predictive model, more precise predictions of process parameters such as material preheating, surface heat treatment, and surface roughness improvement can be made in the future. In this paper, the finite element analysis software MSC Marc is used to calculate the temperature field. The laser temperature field is assumed to be a Gaussian distribution and scanned in a circular path. Linear motion is also performed while rotating. This path increases the range of heat affected zones.