In order to investigate the effects of the dry bulk density and moisture content on the fracture toughness of compacted clay, a new method for the three-point bending test was used, in which the testing sample was rotated 90° in forward around its long side at the bottom, and the loading direction was thus turned to the horizontal direction, perpendicular to the direction of the gravity of the testing sample, so as to avoid the influence of its self-gravity on the fracture extending along the thickness and length of the soil beam. Laboratory tests on the I-type fracture toughness of high-plasticity compacted clay formed by rock weathering in the Jurassic formation in Chongqing City show that the fracture toughness of compacted clay increases with the dry bulk density, and that it increases first and then decreases with the increase of the moisture content, with an optimum moisture content existing, corresponding to the greatest fracture toughness.