Abstract: Annealing is a necessary means to reduce the residual stress and no-load loss of three-dimensional coil core. In the actual annealing process, it is impossible to measure the temperature and stress distribution of 3D coil core in real time and difficult to formulate the annealing process accurately. Due to the material characteristics and coiling process of 3D coil core, an orthotropic thermal mechanical coupling model of 3D coil core was established. Annealing simulation experiments were carried out on the raw materials of 3D coil core, and the optimal annealing cycle of grain-oriented silicon steel was obtained. The annealing cycle of 3D coil core was optimized according to the coil cone temperature and experiment results, and the annealing time was shortened by about 600 min. The correlation between stress, plastic strain and furnace temperature was analyzed. Finally, the optimization scheme of 3D coil core annealing process was given.