Abstract In this paper, the microdistinguishability of electron was discussed by means of analyzing space orientation of electron spin magnetic moment (or magnetic pole). There are 8 kinds of spin configurations within the two electrons. Among them 4 kinds of coupling configurations, are attrative in their spin magnetic poles, and 4 kinds of no-coupling configurations are mutual repulsive in their spin magnetic poles. There are 4 kinds of coupling configurations in spin-orbital movement of electrons. There must be 8 electrons in outmostorbitals of atoms for complete coupling of magnetic poles of spin and orbital, hence, the element periodic law shows a octet rule. Magnetic moment coupling including spin and orbital is essence for chemical bonding and then the attraction of different nuclei. The generalized express language of chemical bond: the chemical bond can only consist of magnetic moment coupling electrons. Wave-particle dualism and the uncertainty principle of electron can be explained by new theory, and their physical model is consistent with the distinguishability nature of electrons.