The invention discloses a method for calculating the concrete dynamic shearing strength by a Hopkinson pressure bar. A cylinder concrete test piece is arranged on the Hopkinson pressure bar; the two axial ends of the cylinder concrete test piece are subjected to dynamic pressurization, so that the test piece is subjected to shearing force loading; the dynamic shearing strength tau of the material is obtained through calculation by using epsilon i(t), epsilon r(t) and epsilon t(t) measured by the device, the elasticity modulus E of the Hopkinson pressure bar, the cross sectional area A0 of the Hopkinson pressure bar, the cylinder test piece radius R and the cylinder test piece sheared length H. The method has the advantages that by the method provided by the invention, the Hopkinson pressure bar can be used for measuring the concrete dynamic shearing strength; the use range of the Hopkinson pressure bar is expanded; meanwhile, the concrete dynamic shearing performance can be deeply studied; the problem that the dynamic shearing strength of the concrete under the short-time high strength load effect is difficult to measure and calculate is solved.