Abstract: In order to master the service characteristics of mandrel in hot extrusion process of steel pipe and improve the service life of mandrel, a thermodynamic coupling model of mandrel in hot extrusion process of 304 stainless steel pipe was established, and the finite element simulation of hot extrusion process of steel pipe was carried out. The temperature field,stress field and friction force of H13 mandrel during hot extrudsion were analyzed under different friction coefficient,extrusion speed and heating temperature of pipe billet. The results show that the highest temperature and stress of the extruded mandrel are located near the area corresponding to deformation zone and sizing zone of the mandrel. These two locations are the most prone to failure. With the increase of friction coefficient, the temperature rises, stress and friction force of the mandrel in the extrusion process increase obviously. The extrusion speed has little effect on the temperature, equivalent stress and friction force of the mandrel. The heating temperature of the pipe billet has little influence on the temperature and stress of the mandrel, but has a great influence on the friction force. The higher the temperature of the pipe billet, the smaller the friction force of the mandrel.