In this paper, electron-beam furnace was used to purify 99.8% industrial pure praseodymium.It studied the effect of melting parameters of the electron beam such as different power and melting time on the impurities extraction, and analyzed the distribution of the impurity element in the praseodymium ingot.The results show that the purities of praseodymium are all lower than 99.95% after purifying, and the main impurity elements Si, Ca, Mg, Fe, Mn, AI, Ni, Co, Cu, Pb, Zn, Cd and Cr were not detectable or at very lower values following the purification.The impurity ratios of Mo and W show no purification with the growth of time,otherwise, the impurity ratios illustrate increase to some extent.The elements Ti were partially removed, the higher the power and time, the better the removal efficiency of impurities.However, with time extended, Ni/NiO no longer reduces and tends to stabilized.The melt temperature was estimated by praseodymium weight loss and measured chemistry changes.Impurity ratios Ni/NiO calculated using Langmuirs equation for ideal vaporization into a vacuum are in good agreement with measured values.The segregation effect cause the solute atoms redistribute in the solid and liquid phases.The loss rate of praseodymium grows linearly with the time and power increase.