Although　low　solid　solubility　and　activity　of　LiFeO2　in　xLi(2)MnO(3)center　dot(1-x)LiFeO2　limit　its　practical　application,　it　still　has　the　potential　to　become　a　new-generation　cathode　material　without　cobalt　or　nickel　for　Li-ion　batteries.　In　order　to　understand　the　effects　of　the　local　structures　of　different　LiMO2　(M　=　Co,　Ni,　Fe)　layered　materials　on　their　solid　solubility　in　Li2MnO3,　partial　densities　of　states　are　calculated　to　determine　the　Jahn-Teller　distortion　in　the　layered　cathode　material,　and　the　first-principles　calculation　method　based　on　density　functional　theory　is　used　to　optimize　and　compare　the　local　structures　of　LiCoO2,　LiNiO2,　LiFeO2,　LiMnO2,　and　Li2MnO3.　The　degrees　of　distortion　of　the　transition　metal-oxygen　(M-O)　and　lithium-oxygen　(Li-O)　octahedra　in　the　crystal　structure　of　the　material　are　evaluated.　It　is　clear　that　the　solid　solubility　of　layered　materials　is　related　to　the　bond　lengths　and　degrees　of　distortion　of　the　M-O　and　Li-O　octahedra.　Among　them,　the　similar　bond　length　of　LiNiO2　and　Li2MnO3　and　the　high　distortion　of　NiO6　enhance　the　solid　solubility　of　LiNiO2　in　Li2MnO3.　Owing　to　the　absence　of　Jahn-Teller　distortion　in　LiFeO2　and　LiCoO2,　the　FeO6　and　CoO6　octahedra　are　slightly　distorted,　thereby　decreasing　the　solid　solubility　of　LiMO2　(M　=　Fe,　Co)　in　Li2MnO3.　Understanding　the　relation　between　intra-octahedral　distortion　and　solid　solubility　provides　simple　and　efficient　evidence　for　comparing　the　solid　solubilities　of　different　LiMO2　layered　materials　in　the　Li2MnO3　of　Li-rich　cathode　materials.　This　study　can　be　used　as　a　reference　for　component　design　in　Li-rich　materials.