本文利用多元函数微积分和张量分析手段，给出了三维k空间中等能面非球面时半导体电子有效质量的表达式，进而讨论了硅和锗等半导体中电导有效质量的各向同性问题．对这一问题的探讨有助于促进学生理解半导体能带结构及其对导电性的影响．

In this paper the expression of electron effective mass of semiconductors is deduced when the 3D kspace equienergy surfaces are not spherical by using multivariable calculus and tensor analysis. Then, it is discussed whether the conductivity effective mass tensors of Si and Ge are isotropic. The discussions can promote students′ understanding of energy band structures of semiconductors and its influence on conductivity.