应用固体与分子经验电子理论计算了Ｔｉ３Ａｌ及加入Ｎｂ后各相的价电子结构，并从均匀变形因子α、解理能Ｇｃ及位错行为等方面分析了Ｎｂ对Ｔｉ３Ａｌ脆性的影响。结果表明，Ｎｂ使α２相部分无序化，产生新的韧性相，提高了Ｔｉ３Ａｌ合金的α和Ｇｃ值；同时Ｎｂ也减弱了ＴｉＴｉ共价键，增加了基面滑移，从而综合导致Ｔｉ３Ａｌ脆性有本质改善。 The valence electron structures of Ti3Al and each phase after addition of Nb were calculated based on the empirical electron theory of solid and molecule. The influence of Nb on the brittleness of Ti3Al was also analyzed from the uniform deformation factor α, the cleavage energy Gc and the dislocation behavior. The results show that Nb partially disordered the α2 phase, resulting in a new ductile phase and increasing the α and Gc values ​​of the Ti3Al alloy. At the same time, Nb also weakens the TiTi covalent bond and increases the base slip, which leads to the combination of Ti3Al brittleness is essentially improved.