The invention discloses a testing method for dynamic crack arrest toughness of an I-type crack under a middle-low speed impact load, and belongs to the technical field of rock and concrete engineering. A test piece is a V-shaped side open single crack half-bordered test piece designed by an inventor. The test piece has a V-shaped bottom boundary, and generates an oblique-upward compression wave under an impact load, and the horizontal component of the compression wave has a compression effect on an expansion crack, thereby further preventing cracking of the expansion crack. The testing methodadopts a middle-low speed drop hammer impact test device, finite element difference software AUTODYN is used for simulation calculation, and results are basically consistent with test results. An obtained load stress time history curve is inputted into finite element program ABAQUS, and a time-history curve of a dynamic stress intensity factor of the I-type crack is obtained. Finally, the dynamiccrack arrest toughness of a material is determined by the crack arrest time of the crack. The testing method for the dynamic crack arrest toughness of the pure I-type crack under the middle-low speedimpact load has the advantages of simple test piece configuration, easy processing, simple and clear test procedure and convenient operation, and is suitable for the research of crack dynamic expansion behaviors and dynamic fracture toughness tests.