We investigate the effects of niobium (Nb) on helium (He) dissolution and diffusion behaviors in tungsten (W) using a first-principles method. The results show that Nb can effectively reduce the solution energy of He in the bulk W, which is because of the charge density redistribution. This leads to a strong attraction between He and Nb in W, and thus Nb can serve as a He trapping centre in W. The trapping energy of He is 0.37 eV at the most stable site surrounding Nb atom. It is demonstrated that the diffusion barrier of He towards Nb will decrease with the decreasing of He-Nb distance. This suggests that the kinetic process in which He is trapped by Nb is feasible. Therefore, the presence of Nb will facilitate the nucleating and blistering of He in W.%采用第一性原理计算方法系统研究了合金化元素铌(Nb)对钨(W)中氦(He)溶解和扩散行为的影响.研究发现， Nb的存在显著降低了He在W中的溶解能， Nb可以作为W中He捕陷中心，在最稳定位置处Nb对He的捕陷能达到0.37 eV.通过电荷分析发现，这主要是因为Nb的存在引起了W中电荷密度的重新分布.而He在W中的扩散能垒将随着He-Nb间距离的缩小逐渐降低，这从动力学上表明He被Nb捕陷是可行的.因此， Nb的存在将有利于W中He的聚集成泡.
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