Abstract: The basic research was reviewed about the weathered crust elution-deposited rare earth ore for over forty years, including the causes and the characteristics of the deposit, the compositions and properties of rare earth ore, the relationship between rare earth ore and clay mineral as well as the theory of the adsorption and migration of rare earth in the clay mineral. Great attentions were also paid to the characteristics of the rare earth element partitioning and the four major effects in the weathered crust elution-deposited rare earth ore. The leaching mechanisms were investigated and the three generation leaching technologies of the weathered crust rare earth ore were also reviewed. The fundamental research, the development of the leaching technology and the problems which should be resolved urgently in the weathered crust elution-deposited rare earth ore were pointed out.