As a key component of wind turbine, the surface strengthening treatment of wind turbine gear is crucial to enhance its performance and service life. In the process of tooth by tooth induction heating of wind power gear, to clearly define the temperature distribution and process evolution, could realize the lean control of heating effect and quality. In this paper, the tooth by tooth heating process under v-shaped inductor was studied to analyze the temperature field morphology and its evolution process. The results show that in the tooth profile region, the boundary morphology of the temperature field that near the central section of the heating region conforms to the Boltzmann function, while the far sections conform to the normal distribution. At the end of heating, from the surface to the depth of the heating layer, and from the heating center to both sides, the maximum temperature difference and the distribution temperature are both reduced. Meanwhile, the maximum temperature point near the central section is offset during the evolution of the temperature field morphology. The change of physical properties of materials and induced eddy distribution caused by involute structure and the constant change of temperature gradient are the fundamental reasons for the appearance of non-uniform temperature field and temperature excursion. The spatiotemporal variation of the hottest point was found, and the temperature morphology and evolution were revealed, which would provide a theoretical basis for adjusting the temperature distribution of tooth profile according to the requirements of different heating layers.