In order to research the fracture toughness of compacted clay, a new apparatus of fracturing test is proposed. Based on the new apparatus, the fracture toughness of the clay were tested, the rationality of the test methods was discussed. Combined with the results of previous studies, the relationship between the fracture toughness and the tensile strength was discussed. The results shown that, the crack propagation characteristic of the compacted clay matched with the linear elastic fracture, research the crack propagation by Linear Fracture Mechanics is apposite. The linear relationship between the fracture toughness and the tensile strength was found. But the nature of the soil particles, the particle curves, the sample water content, the test methods and others could in impact the fracture toughness, which need for more research.