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 本文提出了电子自旋空间的对称面概念，分析了电子自旋的本征态以及电子自旋角动量分量的平均值的问题，并讨论了自旋态的相因子问题。
