The invention discloses a method and device for obtaining anisotropy of rock fracture toughness, and belongs to the field of rock mechanics evaluation. According to the invention, the method comprisesthe steps: carrying out the axial grooving repeated scribing and axial fracture repeated scribing in the axial direction of a first rock core, and obtaining a continuous section of the axial fracturetoughness of the first rock core under different axial scribing depths and different axial scribing distances when the first rock core is in a brittle failure state; performing circumferential grooving repeated scribing and circumferential fracture repeated scribing in the circumferential direction of a second rock core; when the second rock core is in a brittle failure state, obtaining a continuous section with circumferential fracture toughness under different circumferential scribing depths and different circumferential scribing distances, and obtaining the anisotropy of the rock fracturetoughness in the well depth direction, thereby providing a basis for well selection and layer selection of fracturing construction. Moreover, the first rock core and the second rock core do not need to be fractured in the test process, and the first rock core and the second rock core can be repeatedly used after the test is finished, so the waste is avoided.