The concept of symmetry plan of electron spin space was put forward in this paper . the problems on eigen state of electron spin and average value of spin angular momentum projection and also on the problem of phase factor of the spin - state were analyzed and discussed 本文提出了電子自旋空間的對(duì)稱面概念,分析了電子自旋的本征態(tài)以及電子自旋角動(dòng)量分量的平均值的問題,并討論了自旋態(tài)的相因子問題。