Abstract: The thermal extrusion finite element model of Cu-15Ni-8Sn alloy bar with diameter of 100 mm was constructed based on the experimental data of thermal compression. MSC.Marc software was used to simulate the thermal extrusion process, the distribution of temperature, strain rate, stress and grain size were analyzed, and the parameters of hot extrusion process were optimized. The results show that the distribution of stress, strain rate, temperature and recrystallization grain is not uniform during hot extrusion. The temperature of the contact part between the sample and die is the lowest due to the heat conduction. At the same time, the temperature at the die outlet is higher than that at the die inlet due to the heat generation by friction and deformation; the distribution law of stress and strain rate is the same, and the maximum value appears at the entrance and exit of die; the grain size at the contact area between the sample and die cone angle is the smallest. The optimized hot extrusion process parameters are the extrusion temperature of 900℃ and extrusion speed of 4 mm/s.