The invention relates to an austenitizing determination method in a metal material heat treatment process, and belongs to the technical field of multi-field coupling numerical simulation, and is usedfor solving the technical problems that existing numerical simulation cannot obtain thermophysical property experimental data of a material in a high-temperature stage and the influence of phase change and thermophysical property parameter difference on a multi-field coupling calculation result is not considered when material components are changed. The method comprises the following steps: S1, establishing a method for acquiring phase change and thermophysical parameters of a material according to components and temperature of a metal material; S2, establishing a finite element model of a thermal coupling calculation or heat transfer calculation of a temperature field-stress field; S3, calculating the temperature field or thermal stress of the metal material; S4, acquiring the distribution condition of the temperature field and the thermal stress of the metal material along with the time change; and S5, obtaining an austenitizing determination result in the heat treatment process of the metal material. According to the method, the influence of components on thermophysical parameters and phase change stress is considered, the influence of phase change on a temperature field and residual stress can be accurately calculated, and the method is used for optimizing the heat treatment process of different materials.