The wedge splitting test according to Tschegg represents a frequently applied method for the characterization of the fracture mechanical behavior of refractories. The tests permits the determination of the specific fracture energy and the nominal notched tensile strength but does not provide a direct way of calculation for the Youngs modulus and the tensile strength. Moreover, in case of residual loads, it is not always possible to get an accurate value for the specific fracture energy. Therefore an inverse approach for the determination of the material parameters Youngs modulus, tensile strength and specific fracture energy based on finite element simulations was investigated. For that purpose, the load displacement curves of the test and the simulation, respectively, are compared and fitted. The fitting is done by the variation of the material parameters applying the algorithm according to Levenberg-Marquardt. For the finite element simulations a linear strain softening in dependence of the crack opening was chosen. The inverse determination turned out to be an appopriate method for the fitting of the curves. For the determination of representive values for the material parameters further investigations are necessary. These investigations should imply the application of a bilinear strain softening and a crack formation confined to the ligament surface of the specimen.