In this article, a mathematical model was developed to investigate the electron beam melting (EBM) process of vanadium alloys. The temperature distribution of molten V-4Cr-4Ti alloy was obtained by using the model. The effects of different parameters of electron beam melting process on the temperature field and the shape of molten pool were studied. The results showed that the temperature field and the shape of molten pool were influenced by the melting power and scanning radius. With the melting power increasing, the max melt temperature increased linearly and the width and depth of molten pool increased gradually. With the scanning radius increasing, the max melt temperature increased first and then reduced. The optimized parameters of refining vanadium were obtained, and the accuracy of the model was validated by the experimental data.