The hot extrusion deformation process of TA15 titanium alloy was simulated by the FEM software MSC Marc. The distribution of equivalent stress field and the equivalent strain field was obtained. The post treatment for the data based on the simulation results including stress and strain was carried out. The division of deformation was proposed by employing the characteristic quantity such as Lode parameter and invariant of the deviator (J2). Based on the simulation results, the divisions of deformation and the divisions of the plastic deformation types, the sampling to the samples of the hot extrusion was made. Microstructure observation was carried out at different temperatures and the evolution rule of the microstructure was analyzed. It has great significance for the metal hot extrusion forming analysis and its application