Abstract: Damage, stripping and other unfavorable phenomena often occur at the interface of a high roller compacted concrete (RCC) gravity dam where exists a mutation in material characteristics, threatening dam safety to a certain degree. In this work, to avoid leakage problems and improve deformation coordination, we arrange a transition layer using new impervious material HIAC between the impervious layer and the main body of RCC dam, and design three schemes of rectangular, two-step and three-step transition for this functionally graded structure. We examine spatial variation in the elastic modulus of the transition layer from the perspective of deformation coordination, and evaluate the stress and deformation in the whole structure and material interface of the dam using the contact analysis theory. Results show that when the elastic modulus of the transition layer is higher than that of the main body RCC, the principal tensile stress in the dam is at a low level and the HIAC and RCC materials are well coordinated in their normal and tangential deformation. The present study recommends the three-step transition structure that should have an elastic modulus not lower than the main body RCC. The concept of deformation coordination developed in this study is useful and would provide a new angle for evaluation of the construction and operation of RCC gravity dams.