The lithium ion(Li-ion) batteries, known for their high energy density and high energy conversion efficiency, have been widely applied in portable electronics and electric transportation. With reversible capacities over 300 mAh·g^-1, the Li-rich layer-structured oxides are important candidiates of the cathode materials for the Li-ion batteries with energy densities of 350 Wh·kg^-1 or higher. However, the issues related to the structural degradation during long-term cycling and the high surface/interface sensitivity(dissolution of the transition metal ions and the side reactions with the electrolyes) have to be well addressed before these materials can be commercially applied. This review is to present some of our efforts in stabilizing the structure and electrochemical performances of these materials by way of elemental substitution in the bulk and on the surface and by designing new structures, on the basis of comprehensive understandings on their crystalline and electronic structures and the structural evolution. Meanwhile, for the purpose of providing the audience with some overview about the world-wide research progress on these oxide materials, some important achievements are introduced including homogeneous elemental substitution in the lattice, structurally integrated surface modification(such as multilayer modification and construction of concentration-gradient materials), surface coating and surface doping. We will share our thinking on the research directions of these materials before ending this review.